Tigers on the board
England international Toby Flood delivered a virtuoso display as Leicester kick-started their Heineken Cup campaign with a 39-22 victory at Welford Road.
Flood scored 24 of Tigers' points, including a decisive interception try nine minutes from time when he caught his opposite number Dan Biggar's speculative pass and raced 60 metres to score.
He also kicked five penalties and two conversions, with his fellow England internationals Manu Tuilagi (2) and Ben Youngs adding touchdowns as Leicester opened their account in Pool Two after last weekend's defeat in Toulouse.
It was rough luck on Biggar for conceding the Flood try, as he also made a high-class contribution with 17 points that included the conversion of flanker Ryan Jones' early try.
But Leicester secured an unlikely bonus point triumph with a blistering onslaught of 20 points in the last 18 minutes to leave the Ospreys shell-shocked.
The closing stages showcased Leicester at their finest, sensing an unlikely maximum points haul when they could have just settled for a hard-earned win.
Youngs, a thorn in the Ospreys' side all afternoon, continued to cajole his team-mates, and he inspired the late flourish by sprinting over for a try after Tigers' attackers made the most of a kind bounce.
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And there was worse to come for the Ospreys with the last play of a gripping encounter when flanker Steve Mafi was held up short, but Tuilagi gathered possession and gleefully dived over to send a 20,000 crowd wild.
Ospreys could scarcely believe the quality of Leicester's finish, and they will head back to Wales without even a losing bonus from a game that saw them go hammer and tongs with their opponents for most of the contest.
Both teams were unchanged following their opening European fixtures, with Leicester looking to bounce back from defeat in Toulouse and Ospreys targeting another victory after a bonus point success against Treviso.
And it took the visitors just 96 seconds to breach Leicester's defence, carving them open through wing Hanno Dirksen's pace after a Youngs fumble before Jones provided a close-range finish.
Biggar converted, before the Ospreys almost struck again when full-back Richard Fussell's fifth-minute break had Tigers retreating in all directions until the move fizzled out.
But when Biggar kicked a penalty from the halfway line, Leicester were given further food for thought, trailing 10-0 little more than midway through the opening quarter.
Leicester were stung into action, and they responded promisingly through some sustained territorial pressure sparked by Youngs' slick service and some menacing midfield running by Tuilagi.
Flood opened Tigers' account with a 28th-minute penalty - the product of an Ospreys' scrum offence - and it coincided with Leicester's back division starting to make inroads.
And the Ospreys could only hold out until eight minutes before half-time, being undone by a scintillating move that featured an incisive break from wing Vereniki Goneva, crisp link work by Youngs and a touchdown wide out for Tuilagi.
It was a superbly-executed try that Flood converted, but just when the Ospreys needed to regroup, they had prop Ryan Bevington sin-binned by French referee Romain Poite for a scrummaging infringement, handing Leicester a temporary numerical advantage.
Leicester ended a high-tempo half on the front foot, having hauled themselves level and looking capable of moving up another gear after recovering impressively from an uninspiring opening.
Biggar, though, struck first for the Ospreys after half-time, booting another long-range penalty before Flood cancelled out his kick with an equalising effort.
Youngs continued to test the Ospreys' defence, and a scorching break from inside his own half almost resulted in a memorable solo try, but wing Eli Walker's timely intervention thwarted Leicester.
Adam Jones then departed because of a knee problem that initially surfaced during the opening minutes, and two further Flood penalties in quick succession opened up a six-point advantage as the Ospreys floundered.
But Biggar dragged them back into contention, slotting two penalties in five minutes as he matched Flood's accuracy to tie the game up again entering the closing quarter.
The closing stages belonged entirely to Leicester, though, as Tigers cut loose with tries by Flood, Youngs and Tuilagi and confirmed themselves once again as serious Heineken Cup contenders.