A quadruple from hooker Dewi Lake set Ospreys en route to victory against Benetton Rugby in Pool 2 of the EPCR Challenge Cup, edging a 43-34 win in Swansea.
In a thrilling first half, Ospreys took the lead three times - only to be pegged back on each occasion.
A brace from Lake and one from prop Gareth Thomas came after sustained pressure and power from the hosts, and all three were converted by Owen Williams.
But Benetton clawed back parity each time courtesy of a brace from Onisi Rateve on the wing and one from flanker Sebastian Negri da Ollegio, with Jacob Umaga adding the extras.
The fly-half put the visitors in front for the first time on the stroke of half-time with a penalty.
The second half was just as close; a try for Paolo Odogwu was sandwiched between two more for Lake.
And Morgan Morris crowned the win with a 76th-minute try, converted by Jack Walsh, with Benetton down to 14 after a yellow card for Mirco Spagnolo.
Umaga made the last few moments interesting with a penalty in the 79th minute, but Ospreys saw it out - with Walsh scoring a penalty himself in the final seconds.