OSPREYS substitute Jonathan Spratt scored a 77th-minute try to deny Leicester victory in their Heineken Cup clash at the Liberty Stadium.
The visitors looked to have done enough through second-half touchdowns from scrum-half Ben Youngs and wing Niall Morris, though they trailed for much of the contest after the home side went in front thanks to a Joe Bearman try.
Dan Biggar and Toby Flood each kicked a conversion and penalty, but the Ospreys would have won had Biggar not missed four penalties and a late conversion.
Biggar was totally out of luck as two of his attempts struck the post and another hit the bar.
A breakaway inspired by Ospreys scrum-half Kahn Fotuali'i cut open Leicester's defence and it took a fine tackle by Mathew Tait on home flanker Justin Tipuric to snuff out the threat.
But further pressure gave Biggar another penalty chance, which this time he landed.
The home pressure eventually paid off six minutes before the break when the ball was recycled quickly and Bearman strode over.
Biggar landed the conversion.
Flood kicked a penalty to open Leicester's account.
The Tigers delivered an equalising try after the break when Youngs sniped his way over for a score that Flood converted.
Morris struck with eight minutes remaining, but the Ospreys were not finished and a break from Eli Walker caused enough mayhem in Leicester's defence for Spratt to finish off.
Biggar's conversion attempt was wide.
The visitors looked to have done enough through second-half touchdowns from scrum-half Ben Youngs and wing Niall Morris, though they trailed for much of the contest after the home side went in front thanks to a Joe Bearman try.
Dan Biggar and Toby Flood each kicked a conversion and penalty, but the Ospreys would have won had Biggar not missed four penalties and a late conversion.
Biggar was totally out of luck as two of his attempts struck the post and another hit the bar.
A breakaway inspired by Ospreys scrum-half Kahn Fotuali'i cut open Leicester's defence and it took a fine tackle by Mathew Tait on home flanker Justin Tipuric to snuff out the threat.
But further pressure gave Biggar another penalty chance, which this time he landed.
The home pressure eventually paid off six minutes before the break when the ball was recycled quickly and Bearman strode over.
Biggar landed the conversion.
Flood kicked a penalty to open Leicester's account.
The Tigers delivered an equalising try after the break when Youngs sniped his way over for a score that Flood converted.
Morris struck with eight minutes remaining, but the Ospreys were not finished and a break from Eli Walker caused enough mayhem in Leicester's defence for Spratt to finish off.
Biggar's conversion attempt was wide.