Leinster's crushing win over Scarlets came just weeks after Ireland's Grand Slam triumph and Sexton has praised the "professionalism and mental hunger" of the new kids on the block.
James Ryan, 21, Jordan Larmour, 20, and Dan Leavy, 23, are enjoying breakthrough seasons, and Sexton has been impressed with what he has seen.
"The professionalism for their age is incredible," Sexton told the BBC. "With the Irish team the same guys came in and brought a freshness and an unbelievable mental hunger.
"It doesn't happen by chance - these guys had to bide their time last year, and they are taking their opportunities now."
Leinster now face Racing 92 in the European final in Bilbao on 12 May, before focusing on the Pro 14 play-offs, and Sexton is well aware of the challenge that is on the horizon.
"A few more games [to win] to make it a very special season,' Sexton added. 'But our toughest test is ahead of us."