Tom Varndell's two tries proved decisive
Leicester: (28) 41
Tries: Varndell (2), Croft, Kay, Tuilagi
Cons: Burke (4), Goode
Pens: Goode (2)
Ospreys: (9) 35
Leicester survived a strong second-half Ospreys fightback to secure the EDF Energy Cup at a scorching Twickenham.
Tries: Byrne, Williams (2), Walker
Cons: Hook (3)
Pens: Hook (3)
The Welsh side paid the price for their awful, error-ridden first half as they conceded soft tries to Tom Varndell, Tom Croft, Ben Kay and Alesana Tuilagi.
After the break the Ospreys closed the gap to three with scintillating tries from Lee Byrne and Shane Williams (2).
But Tom Varndell's second score proved decisive, Nikki Walker's late try not thwarting the treble-chasing Tigers.
Ospreys number eight Ryan Jones was carried off near the end with a worrying looking leg injury, but early reports suggested that the problem was not as bad as initially feared.
The Ospreys, bidding to become the first Welsh side to win the competition, had targeted the final as their coming of age as a European force and brought a huge travelling support to the 60,000 crowd.
They started with purpose, strong forward drives laying the platform for two early James Hook penalties.
Marshall had a nightmare first half for the Ospreys
But the turning point came in the 12th minute as Paul Burke - preferred to Andy Goode at outside-half by Leicester - put in a delightful chip over the Welsh defence.
Justin Marshall was on hand to cover, but Varndell ripped the ball from the scrum-half's grasp to cross under the posts.
Two minutes later, a Burke cross kick from deep in his own half was tapped back by Croft, the ball falling kindly to Dan Hipkiss.
The impressive centre burst forward and found Croft in support, the flanker showing great pace to finish from 45 yards.
The Ospreys were pushing the self-destruct button with Marshall - so impressive in the semi-final win over Cardiff Blues - having a nightmare.
The ex-All Black star lost possession after carrying into contact on his own 22, and the ball fell to Kay who had an unchallenged canter to the line.
With the half hour mark yet to have passed, man-of-the-match Hipkiss found Tuilagi after another neat break and the imposing Samoan wing brushed Marshall aside for the fourth try.
With the Tigers dominating the set pieces and contact, the Welsh side's only response was a third Hook penalty as they began the second half 28-9 behind.
An early Ospreys assault went unrewarded as Adam Jones and Filo Tiatia blew a try-scoring chance in the corner.
But Leicester had lost Burke to injury at half-time, and a loose clearance kick from replacement Goode fell to Walker.
The Scotland wing carried powerfully and from swiftly recycled ball Williams got a beautiful pass out of the tackle to send Byrne in at the corner.
The Tigers drove back, but Martin Castrogiovanni lost possession in the Ospreys 22 under a heavy tackle from Huw Bennett.
The ball was spun wide to Walker who made good ground before feeding Byrne.
The Ospreys rattled the Tigers with their attacking flair
His long, looped pass found Williams, whose lightning acceleration took him away from the defence for a dazzling try.
Goode landed a penalty after a strong Leicester scrum, before another Walker break set the position for the third Ospreys try.
The Tigers' defence was stretched to breaking point by repeated Ospreys attacks, Williams finally able to squeeze out of Daryl Gibson's tackle for his second score.
But Ospreys' hopes were scuppered by a well-worked Tigers try, Tuilagi used as a dummy runner in midfield as Hipkiss made the crucial break, then found Varndell on the outside who had too much pace for Walker.
The Ospreys again came back, Walker having the power and reach to barge over in midfield from short range.
But the Tigers - who still have the Guinness Premiership and Heineken Cup in their sights - held on to claim England's premier knockout cup for the sixth time.
Leicester: Vesty, Varndell, Hipkiss, Gibson, A. Tuilagi, Burke, Ellis, Castrogiovanni, Chuter, White, Cullen, Kay, T. Croft, S. Jennings, M. Corry.
Replacements: Goode for Burke (40), F. Murphy for Ellis (40), B. Deacon for T Croft (50), Moreno for Castrogiovanni (73), L. Deacon for Cullen (65). Not Used: Hickie, G. Murphy.
Ospreys: Byrne, S. Williams, Parker, A. Bishop, Walker, Hook, Marshall, D. Jones, Bennett, A. Jones, Cockbain, A. Jones, R. Jones, Thomas, Tiatia.
Replacements: Terblanche for Byrne (70), Connor for A. Bishop (79), Spice for Marshall (70), B. Williams for Bennett (68), James for A. Jones (55), Powell for Cockbain (79), Pugh for Tiatia (68).
Referee: A Lewis (Ireland).
Touch judges: S McDowell and P Fitzgibbon (both Ireland).