Cardiff win another penalty as Harry Sheridan didn't roll away.

Sheedy is going to pop the ball into the corner.

Ulster give away a penalty after Zac Ward strayed in front of the kicker, Conor McKee.

Callum Sheedy brings the hosts up to the edge of the 22.

The hosts gather the kick-off and immediately clear, which gives Ulster the ball on halfway.

Off we go!

Here come the teams to a huge noise.

The trio of centurions make their way onto the pitch before the rest of the players, which is a nice touch.

Ian Humphreys
Former Ulster fly-half Ian Humphreys on BBC Radio Ulster

I think it's going to be very close. This Cardiff team have huge experience, but Ulster have a chance, especially with their bench if they can stay in the game.

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Four tries and five points.

It's what both sides want this Christmas.

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Well, would you look who it is!

It won't be long until the teams enter the pitch.

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Ulster head coach Richie Murphy has urged his side to "keep our foot on the pedal" after emerging from the autumn break with a couple of thumping home wins.

After a month without a game, Ulster returned to action with a 47-13 win over Benetton in the United Rugby Championship before opening their Challenge Cup campaign with 61-7 demolition of an understrength Racing 92.

But with a Challenge Cup fixture away to Cardiff today followed by three successive inter-provincial derbies against Leinster, Connacht and Munster, Murphy says his players cannot afford to lose momentum over a demanding festive period.

"We're coming off the back of a couple of good wins. The boys are playing some really good rugby. [We're in a] very positive place," said Murphy.

"We just have to make sure we keep our foot on the pedal and not lose sight of the thing that have made us good over the last few weeks."

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Ulster hooker Tom Stewart says he is getting "into a bit of a groove" ahead of tonight's Challenge Cup trip to Cardiff.

Stewart made an impact off the bench as he touched down one of seven second-half tries as Ulster marked their return to action last week with a commanding 61–7 victory over Racing 92 in Belfast.

The 24-year-old has struggled with injuries in recent seasons but now feels he is getting back to his best form, helped by a run of games heading into a busy festive period that includes successive inter-provincial clashes with Leinster, Munster and Connacht.

"I had that surgery on my ankle there a while ago. I'm starting to feel my body out a wee bit more and things are starting to look up a bit, which is positive," Stewart told BBC Sport NI.

"Getting a good run of games in a bit of time is nice too, getting the flow and feel for rugby. I feel like I'm starting to get into a bit of a groove of things.

"We're getting a run of games there, which is quite nice. Finding a bit of form, coming into Europe and stuff like that is good. We're looking forward to getting this week and then getting a run at the inter-pros."

Tony McWhirter
1999 Ulster European Cup winner on BBC Sounds

Image source, Inpho

Leigh Halfpenny's selection is interesting. He's a goal kicker extraordinaire and he can knock penalties over from anywhere.

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Former Wales full-back Leigh Halfpenny has signed a new contract with Cardiff and returns to action this weekend.

The 36-year-old signed a short-term deal at the start of the season, initially as a kicking coach, with the intention of returning to play once he recovered from a calf injury.

Halfpenny, who will turn 37 just before Christmas, has now agreed a contract to continue at the Arms Park as a player-coach.

He is fit for selection and has been included to start in Saturday's Challenge Cup home match with Ulster (20:00 GMT) in which he would play in a Cardiff side for the first time in more than 11 years.

It will be 4,347 days since his previous appearance for the Blue and Blacks, having left the club for Toulon in 2014.

"We are blessed to have some quality full-backs at the club, but to add Leigh's experience to the mix is brilliant," said Cardiff Rugby coach Corniel van Zyl.

"Leigh has spent time helping our kickers and young full-backs during the past two months but has also worked hard to get himself back fit and available for selection.

"He continues to help the young players on a daily basis and gives us another option and further competition."

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Wing Zac Ward says Ulster must bring their "A game" into tonight's Challenge Cup Pool 3 match in Cardiff.

The Irish province started their European campaign with a thumping 61-7 win over Racing 92 in Belfast while Cardiff lost at Stade Francais.

However, Cardiff came from 19-0 down to win the last match between the sides in the United Rugby Championship in October 2024, and, just like Ulster, have only lost one United Rugby Championship match this season.

Ward, who scored two tries in the win over Racing, said the trip to Cardiff is "going to be really tricky".

"They had our number last season in the URC and we're definitely going over there to right a few wrongs," said the 27-year-old, who added that new attack coach Mark Sexton has allowed the players to "express themselves".

"Both teams want to win, especially in Europe, and we know how important wins are, especially away from home.

"We had a really good start on Friday night against Racing and we'll take the positives forward. It will be a different challenge playing against a really good Cardiff side so we'll need to be on our A game."

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Cardiff pulled off a stunning second-half fightback to beat Ulster and halt their slide down the United Rugby Championship in October 2024.

The hosts trailed 19-0 at half-time as Jude Postlethwaite scored twice after Cormac Izuchukwu crossed during a costly yellow card for Wales hooker Evan Lloyd.

But man of the match Iwan Stephens inspired the comeback with a spectacular score before replacements Dafydd Hughes and Thomas Young followed.

Callum Sheedy’s three conversions gave Cardiff the lead for the first time just 12 minutes from the final whistle before holding out for the win.

It ended a three-game losing run for Matt Sherratt's side while Ulster will wonder how they missed the chance to go fourth in the table.

Instead, Cardiff’s first win over an Irish province in more than two years saw them move level on points with Ulster, whose miserable night was made worse by Iain Henderson lasting just 24 minutes on his return from concussion.

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Tom Stewart will captain Ulster for the first time as head coach Richie Murphy rings the changes for tonight's games.

Stewart, who captained Ireland XV's win over Spain last month, will lead a side showing nine alterations from last week's thumping win over Racing 92 in Belfast.

The 24-year-old replaces Rob Herring at hooker, while loose-head prop Callum Reid also comes into the front row.

Harry Sheridan and Charlie Irvine are retained in the second row, with Sean Reffell and Bryn Ward recalled to the back row.

Murphy has opted to switch up his half-back pairing for the first time this season with Conor McKee and Jake Flannery handed starts, while centre Ben Carson, wing Werner Kok and full-back Stewart Moore are also added to the backline.

Wallabies prop Angus Bell is again named on the bench after making his debut last week. Fit-again Ireland forward Cormac Izuchukwu also makes the bench after missing two months out with a foot injury.

Instonians full-back Bradley McNamara could make his debut after being handed the number 23 shirt. Replacement hooker John Andrew is set for his first appearance since March, while uncapped prop Rory McGuire and James Humphreys are also included.

Jacob Stockdale, Rob Baloucoune, Jude Postlethwaite, Jack Murphy, Nathan Doak, Sam Crean, Rob Herring and Nick Timoney are all rested after starting the Racing game.

Ulster: Moore; Kok, Hume, Carson, Z Ward; Flannery, McKee; Reid, Stewart (capt), O'Toole, Sheridan, Irvine, McCann, Reffell, B Ward.

Replacements: Andrew, Bell, McGuire, Izuchukwu, Augustus, Shanahan, Humphreys, McNamara.

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Cardiff trio Ben Thomas, Keiron Assiratti and Rory Thornton will make their 100th appearances for the region when they host Ulster in the Challenge Cup.

They will bring their milestones up as starters against the Irish province while former Wales and British and Irish Lions fullback Leigh Halfpenny has also been named in the XV.

The 36-year-old signed a short-term deal at the start of the season as kicking coach and is now set for a first Cardiff appearance in more than 11 years, 4,347 days since his previous appearance for the Blue and Blacks.

The hosts are also boosted by the return of wing Josh Adams, who has served his three-match suspension following a red card for Wales against Japan in the Autumn Nations Series.

Cardiff are looking to bounce back from a 38-17 defeat by Stade Francais, while Ulster thumped Racing 92 with an impressive 61-7 win in the first round of fixtures.

Fly-half Ioan Lloyd misses the game after sustaining a shoulder injury in Paris, though he does not require surgery on the injury at this time.

Cardiff welcome back centre Thomas, fly-half Callum Sheedy and tight-head Assiratti to the XV after being with Wales in the autumn, while loose-head prop Danny Southworth, flanker Alex Mann and full-back or centre Jacob Beetham are on the bench.

Cardiff: Halfpenny; Adams, Millard, B Thomas, Bowen; Sheedy, A Davies; Barratt, D Hughes, Assiratti, Nott, Thornton, Botham, D Thomas, Lawrence (capt).

Replacements: E Lloyd, Southworth, Wainwright, McNally, Mann, Bevan, Beetham, Winnett.

Image source, Inpho

Today's venue.

The sun has set and the lights are on at Cardiff Arms Park.

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Ulster secured a commanding bonus-point win over Racing 92 in what was their first ever pool-stage game in the Challenge Cup.

On the night when Australia prop Angus Bell made his debut for the northern province, Richie Murphy's side scored nine tries in the 61-7 victory but almost all of the damage was done in the second half.

The French visitors to the Affidea Stadium rotated heavily for the contest but took a 7-0 lead and Ulster's advantage was just 14-7 at half-time.

The province took control of proceedings with a pair of quick-fire scores after the turn and ultimately scored 47 unanswered points in a dominant second half.

Image source, Inpho

Cardiff suffered a six-try defeat at Stade Francais after being overpowered in the second half of their European Challenge Cup opener.

The Blue and Blacks led 10-5 at the break despite rotating their squad for the trip to Paris because of their strong start to the United Rugby Championship (URC).

Wing Iwan Stephens, on his first appearance since rupturing knee ligaments a year ago, crossed along with debutant full-back Matty Young.

But Stade scored five tries in the second half to start their campaign with a five-point haul.

Cardiff tight-head prop Javan Sebastian went over with five minutes to go but they did not get a sniff of a fourth for a consolation bonus.

It's the second round of the Challenge Cup and Ulster are on the road in Wales to take on Cardiff.

Cardiff lost their opening fixture, while Ulster hammered Racing 92 and both sides have made changes from their opening fixtures.

You can listen to the game on BBC Radio Ulster, with Grace Davitt and Ian Humphreys in studio, and Tony McWhirter and Jim Neilly are on commentary.

We'll also have live updates here, so you'll be able to stay right up to date.