Leicester had the experience but Leinster had the desire and it saw them home.
It was they who handled the pressure the better, driving Leicester backwards, forcing them into uncharacteristic errors and the concession of costly penalties.
Sexton's first opportunity to win the game came and went, his kicking falling surprisingly short but when Leinster were awarded another penalty with just over ten minutes to go, the 23-year-old from St Mary's College managed to hold his nerve and bend the ball inside the far post.
It was by no means his finest strike but, in the end, that mattered not. Leicester had little left and could find no answer to Leinster's defensive resilience nor their seemingly insatiable desire for Heineken Cup glory.
Leinster: I Nacewa; S Horgan, B O'Driscoll, G D'Arcy, L Fitzgerald; J Sexton, C Whitaker; C Healy, B Jackman, S Wright; L Cullen (capt), M O'Kelly, R Elsom, S Jennings, J Heaslip.
Replacements: J Fogarty, R McCormack, D Toner, S O'Brien, Si Keogh, R Kearney.
Leicester: G Murphy (capt); S Hamilton, A Erinle, D Hipkiss, A Tuilagi; S Vesty, J Dupuy; M Ayerza, G Chuter, M Castrogiovanni; T Croft, B Kay; C Newby, B Woods, J Crane.
Replacements: B Kayser, J White, L Deacon, L Moody, H Ellis, M Smith, J Murphy.