La Rochelle retained the Champions Cup as they broke Leinster's hearts for the second year running in a pulsating final in Dublin.
The Irish province opened up a 17-0 lead after scoring three tries in 12 minutes in a scintillating start.
But La Rochelle staged a brilliant fightback that was capped by Georges-Henri Colombe's late try.
It is La Rochelle's second title and denies Leinster a record-equalling fifth triumph.
There were ecstatic scenes among the men in yellow at the final whistle as they completed the biggest comeback in Champions Cup final history.
It was a classic final that gripped a sold-out Aviva Stadium from the first minute when Leinster scored their opening try.
However, having built a commanding lead, the Irish side faded and were left with a familiar sense of agony after losing last year's decider to the side coached by former Munster fly-half Ronan O'Gara.
The defeat means Leinster have lost three finals - they were also beaten by Saracens in 2019 - since winning their fourth title in 2018.
It caps a disappointing climax to their season after also losing the United Rugby Championship semi-final to rivals Munster last week.
La Rochelle in contrast have reaffirmed their status as European club rugby's leading force under O'Gara, who has now won four Champions Cups as player and coach.
More to follow.