La Rochelle v Leinster (15:15)
Rerun of last year's decider, which La Rochelle won 27-26 in Dublin
La Rochelle 6-7 Leinster
The rain is hammering down now as both sides use probing kicks to exploit the conditions and test the back three.
Leinster have won a penalty as Will Skelton goes offside at a ruck and they point to the posts.
Image source, InphoAntoine Hastoy
La Rochelle win the scrum penalty and Antoine Hastoy nails the kick in the pouring rain to reduce his side's deficit to one point.
La Rochelle 3-7 Leinster
Harry Byrne has kicked the ball dead and we go back for a scrum in Leinster's half.
The out-half's kicking has been good, but the mistake means La Rochelle have the opportunity to attack and win a penalty.
They point to the posts...
La Rochelle 3-7 Leinster
The game is getting increasingly scrappy now as both sides struggle in tricky conditions.
Leinster's Harry Byrne will look to clear his lines with a penalty but play has stopped while Andrew Porter receives treatment for a nasty looking cut to the face.
Cian Healy enters the fray as a blood substitution.
La Rochelle 3-7 Leinster
After sustained pressure from La Rochelle, the men in blue have worked their way up the pitch and find themselves with a scrum on the French side's 22 metre line.
Wet, slippy conditions are not helping as the scrum has to be reset a number of times.
Image source, Getty ImagesLevani Botia
Levani Botia is chopped down short of the line by Will Connors but wriggles forward and reaches over the line.
The referee has ruled out the try as Botia was deemed to have crawled forward without first getting back to his feet.
Image source, Getty ImagesLa Rochelle 3-7 Leinster
La Rochelle using their lineout as a platform as they find themselves in Leinster's 22 now.
They earn another penalty and go to the corner once again.
The hosts are now pummeling the Leinster line with carries but Leinster's defence is impressive.
Image source, InphoLa Rochelle 3-7 Leinster
Leinster finding some fluency in attack now and work their way up the pitch but the ball is turned over and La Rochelle have cleared their lines.
Back and forth action so far in the opening quarter.
Image source, Getty Images
Jordan Larmour
A Leinster try was looking inevitable and, sure enough, another tap penalty drew in La Rochelle before Jimmy O'Brien throws the ball wide to find Jordan Larmour in acres of space, who dives over.
Harry Byrne nails the conversion, extending his side's lead.
Image source, Getty ImagesLa Rochelle 3-0 Leinster
Jonathon Danty from La Rochelle and Leinster's Joe McCarthy are given yellow cards after a review of some pushing and shoving off the ball.
Image source, Getty ImagesLa Rochelle 3-0 Leinster
Leinster piling on the pressure now as they have another penalty five metres out.
Dan Sheehan takes the tap penalty, but La Rochelle turn the ball over illegally on their line.
The referee is struggling to keep control as tempers flare between the two sides.
Image source, InphoLa Rochelle 3-0 Leinster
An abrasive start to this game in the pouring rain as both sides struggle to gain the ascendency in the opening stages.
Leinster have a scrum on the La Rochelle 22.
Can the visitors turn territory into points?
Antoine Hastoy
Leinster go offside at the breakdown and La Rochelle get an early shot at the posts.
Antoine Hastoy is accurate from the kicking tee to give his side an early lead.
Image source, Getty ImagesLa Rochelle 0-0 Leinster
Referee Matthew Carley blows the whistle and we're off here at the Stade Marcel Deflandre!
La Rochelle v Leinster (15:15 BST)
Leinster head-coach Leo Cullen on the wet conditions at Stade Marcel Deflandre on TNT Sports:
"Conditions are going to play a huge part in the game, it's going to be quite difficult to play."
Image source, Getty ImagesLa Rochelle v Leinster (15.15 BST)
The teams are finishing up their warm-ups and are almost ready to go as we approach kick-off.
It continues to rain heavily which will make conditions tricky for handling and running rugby.
Not long to go now...
La Rochelle v Leinster (15:15 GMT)
Ireland hooker Dan Sheehan will make his 50th Leinster appearance in Sunday's Investec Champions Cup opener with reigning champions La Rochelle.
The match is a rerun of the last two finals with the French side having won both.
Nine of the Leinster line-up from last season's final start, including Irish quartet Hugo Keenan, James Ryan, Garry Ringrose and Robbie Henshaw.
Harry Byrne replaces injured brother Ross at fly-half.
La Rochelle have named 11 of the starting team that beat the Irish province in last year's decider.
Second row Thomas Lavault will make his 100th appearance and Pierre Bourgarit will captain the side at Stade Marcel Deflandre.
Georges-Henri Colombe, who scored the decisive try in Dublin, is on the bench but the French side are without wing Teddy Thomas, who is suspended.
La Rochelle: Dulin; Leyds; Seuteni, Danty; Favre; Hastoy, Kerr-Barlow; Wardi, Bourgarit (capt), Atonio; Lavault, Skelton; Boudehent, Botia, Tanga.
Replacements: Idoumi, Sclavi, Colombe Reazel, Dillane, Picquette, Cancoriet, Iribaren, Reus.
Leinster: Keenan; Larmour; Ringrose (co-capt), Henshaw; O'Brien; H Byrne, Gibson-Park; Porter, Sheehan, Ala'alatoa; McCarthy, Ryan (co-capt); Baird, Connors, Doris.
Replacements: Kelleher, Healy, Clarkson, Jenkins, Van der Flier, Murphy, Frawley, Ngati.
La Rochelle v Leinster (15:15 GMT)
It's not been a good start in Europe for the Irish provinces, with Ulster and Connacht both on the receiving end of heavy defeats, while Munster were pegged back for a draw by Bayonne.
Bayonne scored a late converted try to earn a 17-17 draw away to Munster in a hard-fought encounter in the opening round of the Investec Champions Cup at Thomond Park.
Munster led 14-3 at half-time but Thomas Dolhagaray converted late after Remy Baget's try.
Image source, InphoBath staged an impressive comeback to secure a bonus-point 37-14 win over Ulster in a gripping Pool 2 opener at the Rec.
Ulster led 14-8 at half-time after Billy Burns and Nathan Doak tries cancelled out Joe Cokanasiga's opener.
But Bath quickly regained the lead after the restart through Tom Dunn and dominated the second half.
After Ulster's Matty Rea was sin-binned, Thomas du Toit, Cokanasiga and Matt Gallagher helped Bath pull clear.
Image source, InphoBordeaux-Begles handed Connacht a 41-5 home hammering in the opening Pool 1 game.
Romain Buros and Damian Penaud notched first-half Bordeaux tries, either side of a Shamus Hurley-Langton score, as the visitors led 12-5 at half-time.
Wing Pablo Uberti added two second-half Bordeaux tries with the rout completed by Buros' second touchdown and a further penalty try.
Image source, InphoLa Rochelle v Leinster (15:15 GMT)
Image source, Getty ImagesLa Rochelle boss Ronan O'Gara has been given a touchline ban for Sunday's Investec Champions Cup opener against Leinster.
The former Ireland fly-half has been handed a one-match suspension by the French National League for ill discipline during last month's Top 14 defeat by Racing 92.
It is O'Gara's fifth suspension from the league since he took over as La Rochelle's director of rugby in 2021, amounting to 21 weeks of punishment.
Meanwhile, La Rochelle winger Teddy Thomas received a five-week ban for a dangerous tackle and will only be free to play again from 31 December.
La Rochelle v Leinster (15:15 GMT)
Image source, Inpho"The first one is always the best. The second one you're happy, but it is not like the first one."
So how would a third European Champions Cup title feel?
La Rochelle wing Raymond Rhule started in the back-to-back final victories over Leinster, the first in Marseille in 2022, before helping his side come back from 17-0 down to win in Dublin this year.
Only Toulon, who reigned from 2013 to 2015, have lifted the trophy three times in a row.
Victory in 2024 would put Ronan O'Gara's side in contention to be rated the greatest European side of all time.
However, with a new format in play and Leinster in their pool, are the defending champions still the favourites? Or will there be someone else holding up the trophy at Tottenham Hotspur Stadium come May?