Before long Ulster are in the attack and some smart hands by Stuart McCloskey and Tom O'Toole leads the ball to Jacob Stockdale, but the full-back can't hold on to the pass and it is a knock-on.

Nathan Doak was down receiving attention but is back on his feet much to the relief of home fans.

Lucas Andjisseramatchi leads the first La Rochelle charge into the Ulster 22, but as the ball is worked right, James Hume is on hand with a superb turnover and Ulster clear.

Andy Gray
BBC Sport NI at the Affidea Stadium

The perfect start for Ulster.

If you want to know how windy it is, Stuart McCloskey is back in his role as the placeholder for the kick to keep the ball steady for Doak.

T'is breezy.

Nathan Doak hammers the ball between the uprights and the flags go up.

That try has brought the fans in to full voice here in Belfast and Ulster are straight back on the attack, winning a penalty inside the visitors' 22.

Iain Henderson points to the sticks.

Tony McWhirter
1999 Ulster European Cup winner on BBC Radio Ulster

Just the perfect start for Riche Murphy's side. They have more than settled.

And the hosts win the penalty. Jack Murphy clears to touch 40 metres from his own line.

Ulster win a scrum inside their own 22. First test of the pack tonight.

Andy Gray
BBC Sport NI at the Affidea Stadium

It's safe to say the ground isn't full.

Even so, those who have braved the conditions have made a good bit of noise as the teams came out.

There's even a few travelling La Rochelle fans who are making their voices heard.

Let's hope it's a good one.

We are under way at a blustery Affidea Satdium, La Rochelle get the ball rolling.

Matt Gault
BBC Sport NI senior journalist

Image source, Getty Images

With four Champions Cups on his CV - two from a decorated Munster playing career and another couple as La Rochelle head coach - it is no shock to hear Ronan O'Gara speak about life in Europe's second tier with a degree of apathy.

As recently as three years ago, O'Gara's side were the blue riband competition's dominant force, triumphing in 2022 and 2023.

But after a couple of knockout exits in the past two seasons, they failed to progress from their pool this time around.

Now, La Rochelle have two possible paths back to the Champions Cup: secure a top-eight finish in France's Top 14 or win the Challenge Cup.

Ninth in the domestic standings, O'Gara brings his squad to Belfast for tonight's Challenge Cup quarter-final against UIster after his much-changed side beat Newcastle in last week's round of 16 encounter.

"We're very aware of what we did in the other competition, we don't really want to be playing in this competition," said O'Gara.

"But sometimes in life you've got to take your medicine and this is where we are. We know why we're here and that's because of not getting what we needed to get out of the Harlequins game [in the final Champions Cup pool game].

"That's all in the past now. We're looking forward to Friday, it'll be a big learning experience but a big challenge, but if we were to show our true hand we could be very interesting."

Tony McWhirter
1999 Ulster European Cup winner on BBC Radio Ulster

It's going to be won or lost up front. The conditions will even it out a bit. From La Rochelle, we will see a large kicking game.

BBC Sounds

You can listen to tonight's game live on BBC Radio Ulster, 5Live Sports Extra 2 and BBC Radio Sounds from 19:30 BST.

Orla Bannon is on presenting duties with Ian Humphreys and Grace Davitt.

Tony McWhirter, a European Cup winner in 1999, joins Jim Neilly on commentary.

Late change to the La Rochelle side. Open-side flanker Kirill Fraindt is replaced by Judicael Cancoriet, with Oscar Jegou being drafted on to the bench.

Just eight teams left. Who will lift the Challenge Cup?

Quarter-finals:

Ulster v La Rochelle

Montpellier v Connacht

Zebre v Dragons

Benetton v Exeter

Semi-final ties (Highest ranked team at home):

Montpellier/Connacht v Zebre/Dragons

Benetton/Exeter v Ulster/La Rochelle

Ronan O'Gara has made three changes to his La Rochelle side, who beat Newcastle Red Bulls 26-18 in the last-16.

Kirill Fraindt comes in at flanker and Lucas Andjisseramatchi shifts to number eight, while Watisoni Waqanisaravi drops out of the matchday 23.

In the second row, Aleksandre Kuntelia replaces Simon Huchet and Ugo Pacome comes in on the right wing for Jules Favre.

La Rochelle are without some key players including captain Gregory Alldritt, Nolann Le Garrec, Antoine Hastoy, Jack Nowell, Australia second row Will Skelton, back row Levani Botia and full-back Davit Niniashvili.

La Rochelle: Ihaia West; Ugo Pacome; Ulupano Seuteni, Adrien Seguret; Hoani Bosmorin; Diego Jurd, Thomas Berjon (capt); Louis Penverne, Gabin Garault, Karl Sorin; Thomas Lavault, Aleksandre Kuntelia; Edouard Richer, Kirill Fraindt, Lucas Andjissermatchi.

Replacements: Tolu Latu, Christian Luaki, Joel Sclavi, Alexandre Kaddouri, Nikolozi Sutidze, Judicael Cancoriet, Sacha Elissalde, Nolhann Couillaud.

Ulster scrum-half Nathan Doak has been passed fit to start against La Rochelle in tonight's Challenge Cup quarter-final.

Doak injured his ankle in the round of 16 win over Ospreys but has recovered to start in Belfast alongside the returning Jack Murphy.

However, hooker Rob Herring is not in the matchday squad after he picked up a calf injury.

Tom Stewart will start in place of Herring, and he is joined in the front row by Australia prop Angus Bell and Tom O'Toole.

Cormac Izuchukwu will make his 50th Ulster appearance in the second row with captain Iain Henderson, while David McCann, Nick Timoney and Juarno Augustus make up an unchanged back row.

Stuart McCloskey and James Hume retain their places at centre, while Zac Ward comes in on the wing as Jacob Stockdale shifts to full-back and Werner Kok completes the back three.

Harry Sheridan has returned from suspension to take his place on the bench while centre Jude Postlethwaite is also named after he sustained a hand injury against Edinburgh in March.

Ulster: Jacob Stockdale; Werner Kok; James Hume, Stuart McCloskey; Zac Ward; Jack Murphy, Nathan Doak; Angus Bell, Tom Stewart, Tom O'Toole; Iain Henderson, Cormac Izuchukwu; David McCann, Nick Timoney, Juarno Augustus.

Replacements: James McCormick, Sam Crean, Scott Wilson, Harry Sheridan, Bryn Ward, Conor McKee, Jake Flannery, Jude Postlethwaite.

Andy Gray
BBC Sport NI

Image source, BBC Sport

The sun from earlier on has been replaced with strong, chilly winds as fans start to stream into the Affidea Stadium.

It's only set to get worse as the game goes on, too.

The posts are currently swaying in the breeze, and this weather is set to play a role when the match kicks off.

Who will it favour more, though?

It's a big night in Belfast as La Rochelle come to town for a huge Challenge Cup quarter-final.

Ulster are just two games away from a spot in the final in Bilbao, but it will be a difficult test against Ronan O'Gara's side.

We'll have live updates right here and you can also listen on BBC Sounds, BBC Radio Ulster and BBC 5Live Sports Extra 2.

Thanks for joining us.