Johnny Sexton admitted that Leinster struggled to find their rhythm after collecting his fourth European Cup in Bilbao.
Captain Isa Nacewa and Sexton kicked Leinster to an absorbing 15-12 victory, with Nacewa’s final kick, less than two minutes from the end, putting the victors ahead for the first time in a contest that failed to get going in an attacking sense.
The Top 14 club were ahead with less than 10 minutes remaining on the clock as they stifled Leinster’s attacking threat throughout the 80 minutes.
Speaking to Sky Sports afterwards, Sexton admitted it was a hard-earned victory to complete an unbeaten season in Europe.
"We did it the hard way, I don't know what to say. We couldn't get going at all during the game," he said.
"They came out and slowed us down at the ruck and that's the way to beat us. But we did it the hard way and I can't believe we're champions again."
On the impact of Stuart Lancaster, who joined Leinster as a senior coach in 2016, having resigned as England boss in the wake of their awful World Cup campaign in 2015, Sexton added: "What a special coach to come in and do what he's done."