Ronan O’Gara’s tactical masterclass as the La Rochelle coach wrestled the trophy away from Leinster with a last-gasp 24-21 Heineken Champions Cup final victory, leaving Sexton floored.
“I am pretty lost for words to be honest, we weren’t at our best,” admitted Sexton.
“We will have to look at it before we point any fingers. It is devastating.
“Fair play to La Rochelle, they came here with a plan. I didn’t see them coming back but we did not clear our lines and we paid the price.”
O’Gara was jubilant after the win, as he reflected on his journey as La Rochelle coach.
“We started a long way away from dreaming of getting to finals. We were second division eight years ago,” said the Ireland legend.
“I have to thank the boys and staff who have made me so proud. It would have been easy to lose today but we have learned from previous finals and found a way to win.
“It wasn’t pretty but I’m very proud. The defence was everything. We could see that if you stand off them they are going to be very, very strong.
"We had to take their time and space away and we knew we had to score tries to win. There was great heart. We could have rolled over, but we didn’t and I think this is the start of something special.
"We could see that if you stand off them they are going to be very, very strong. We had to take their time and space away and we knew we had to score tries to win. There was great heart. We could have rolled over, but we didn't and I think this is the start of something special.
"This is massive for La Rochelle, eight years ago they were in the second tier. We enjoyed it last season, because the Top 14 is such a marathon, we got a bit of a sprint going. We knew that Leinster are usually out of sight in the first half, so when we came in five down at half-time we knew that was OK.
"It feels a little surreal because it was such a tight game."
Leinster coach Leo Cullen experienced very different emotions as he struggled to come to terms with his side’s defeat.
“It has not really hit home, we are licking our wounds,” he admitted.
“It came down to fine margins and a couple of defensive sets, but there is probably a story about how we got into the situation.
“In the last 15 minutes we could have been better. It is a sickener, but credit to La Rochelle.”