Two tries each from Joshua Kenny and Tommy O'Brien, and scores from Garry Ringrose and Max Deegan give Leinster win over Scarlets in Dublin.
Joe Roberts, Tom Rogers and Max Douglas with the tries for the visitors.
Glasgow beat Benetton with bonus point to solidify top spot.
Tries from Johnny Matthews, Fergus Watson, Max Williamson, Seb Stephen and Sam Talakai secure five points for 2024 champions.
Sharks beat Cardiff 21-15 in Durban to move up to 10th in URC.
Man of the match Phepsi Buthelezi scores twice for Sharks and Penxe adds a third as they beat Cardiff despite two tries from Mason Grady.
Taulupe Faletau comes off with injury in second half before Ioan Lloyd penalty earns losing bonus point for Cardiff.
Sharks 21-12 Cardiff
Incidentally, it seems it is not just the UK sporting authorities and television companies guilty of ridiculous scheduling.
As we speak, a stone thrown away South Africa are playing Panama in an international football friendly. That will really help attendances, won't it?
Sharks 21-12 Cardiff
Chris Horsman
Former Wales prop on BBC Radio Wales
Next score is absolutely crucial.
When Cardiff get opportunities they have got to take them.
Sharks 21-12 Cardiff
So, Ben Thomas kicks us underway for the second period - now get involved you lot.
Can Cardiff come back to win this? Thumbs up if you think so, thumbs down if you are besieged by pessimism.
HT: Sharks 21-12 Cardiff
Image source, Huw Evans Picture AgencyRegardless of how tonight pans out, Cardiff fans have had some welcome news this week with the club confirming that flanker Alex Mann has signed a new long-term contract.
Mann's previous deal was set to expire at the end of this season. The Aberdare RFC and Cardiff academy product has played 16 times for Wales and impressed in this year's Six Nations.
"This is obviously my home club, I have been here since I was 16 years old and have a lot of mates here, so it means a lot and I remain really grateful to all of the coaches and staff who have believed in me over the years and given me the opportunity," said Mann.
On Thursday, it was also announced James Botham had signed a new contract to remain at the Arms Park.
HT: Sharks 21-12 Cardiff
Chris Horsman
Former Wales prop on BBC Radio Wales
Apart from that last three or four minutes I think Cardiff did everything right. They defended really well, played at tempo, got the ball to space as quickly as they can.
They frustrated the Sharks side, but ill discipline and inaccuracy allowed the Sharks to get into their 22 and they were ruthless in those positions.
HT: Sharks 21-12 Cardiff
When Cardiff took the lead after 28 minutes, Sharks were down to 14 men and I said they were on the ropes.
And yet, they end the first half firmly in the ascendancy. That changed quick.
JP Pietersen opted to change his entire front row and the decision has completely turned the tide with two scrum penalties leading to two Sharks tries.
Cardiff, with two key forwards off the field with injury, have attacked with force themselves but now have it all to do after the break.
Sharks 21-12 Cardiff
Chris Horsman
Former Wales prop on BBC Radio Wales
In the blink of an eye the dynamics of this game changes just before half-time.
It came from that scrum penalty, they had a lineout, Buthelezi put a target up, then it was up in the air and win the crumbs.
Cardiff were in disarray there, bit of an opportunists try there.
Penxe try, Hendrikse con
Image source, Rex FeaturesThis game has turned rapidly.
Still with 14 men, Sharks strike again as winger Yaw Penxe notches a brilliant individual try. He goes on an arcing run, spots space behind the Cardiff defence, and executed a perfect chip and chase before scoring.
Jordan Hendrickse's first act back on the field is to convert.
Sharks 14-12 Cardiff
JP Pietersen opted to leave his more experienced front rowers on the bench tonight and the scum impact has been immediate as Sharks win another penalty.
Keiron Assiratti was the man pinged and his fellow prop, Corey Domachowski, is off with a head injury.
Sharks 14-12 Cardiff
Chris Horsman
Former Wales prop on BBC Radio Wales
You have to say Cardiff completely parted like the red sea from that scrum.
If you are going to go up, you have to guarantee that your going to put pressure on it.
Buthelezi try, Davies con
Image source, Rex FeaturesOh boy, the ruthless move pays off quickly.
Bulls win a scrum penalty and it is their turn to go from the corner. Off the lineout, Phepsi Buthelezi takes a ball at pace and ghosts under the posts without a defender laying a glove on him.
With Jordan Hendrikse off the field, number nine Bradley Davies adds the extras.
Sharks 7-12 Cardiff
I am not saying JP Pietersen isn't happy - but the head coach has changed his entire front row on the half-hour mark.
His team are just five points down but already, he's seen enough. Ruthless.
Grady try
What a finish from the winger!
From the lineout, the ball goes to ground in midfield but Ben Thomas is there to collect it and chip towards Mason Grady - who judges the bounce before brilliantly stepping and diving over in the corner.
It took Cardiff less than a minute to take advantage of having 15 v 14. Suddenly, Sharks on the ropes a bit here.
Sharks 7-7 Cardiff
Now Cardiff have a man advantage after Jordan Hendrikse is found guilty of a deliberate knock-on in a bid to thwart a Cardiff attack.
Sheedy boots the penalty into the 22 and suddenly Cardiff are in the ascendancy.
Sharks 7-7 Cardiff
For what feels like the 100th time this season, I type about great work from Dan Thomas.
Sharks hammer away in the 22 but after Jason Jennings carries strongly, the flanker is there to win a turnover penalty.
The man could jackal the Incredible Hulk if he needed to. He's having a superb season.
Sharks 7-7 Cardiff
Chris Horsman
Former Wales prop on BBC Radio Wales
Image source, Rex FeaturesThey won't want to lose Mulder, he's a very robust, physical player for a nine.
He's had a couple of nice passes and box kicks as well so they'll want to keep him on the pitch.
Sharks 7-7 Cardiff
Another potential injury blow for Cardiff here as Corey Domachowski goes off for a HIA, replaced by Danny Southworth.
The visitors could soon be two key forwards down here and Johan Mulder is also receving treatement. Seems ok to continue though.
Sharks 7-7 Cardiff
It is a humid night in Durban, and the players will be grateful for the current 'water break'.
Can imagine old school forwards watching this and tutting mind.
'Just got on with it in our day. Only drink we had was beer in the club afterwards'.
We all know one.
Sharks 7-7 Cardiff
Chris Horsman
Former Wales prop on BBC Radio Wales
Fantastic play there from Cardiff. We said when they are in the Sharks 22 they've got to be accurate and they were there.
That was really good from Cardiff, we said to play with tempo and they did that.
Grady try, Sheedy con
Cardiff level as Mason Grady goes over out wide!
So much for the ropey start, that was brilliantly executed.
A series of carries up front leads to another penalty which Liam Belcher runs - and the Sharks run out of defenders before Grady takes Ioan Lloyd's floated pass and cuts over wide on the right. Sheedy does well to convert and Mr. Van Zyl will be a lot hapiper now.
