Treviso had beaten the Ospreys 12-6 in their domestic league six weeks ago and they fought back to cut the gap to six points with a brace of tries from Fijian No 8 Manoa Vosawi and full back Luke McLean.

Kris Burton added the extras and at 23-17 midway through the second half all the momentum was with the visitors. But the Ospreys steadied the ship with a fourth Biggar penalty and then conjured up a grandstand finish.

Biggar's deadly accurate boot allowed him to break through the 250 points barrier in the tournament with a match tally of 18 and his only miss on the night was a touchline conversion.

The four tries came from the enterprising home backs with young wing Eli Walker leading the way with a magnificent strike from 30 metres. On his Heineken Cup debut he showed no nerves as he beat four defenders with two lightening fast side steps on his way to the posts.

Opposite wing Hanno Dirksen grabbed two second half tries before Beck rounded off proceedings with his last gasp effort. Treviso hit back gamely, but their scrum was destroyed and they suffered from having three yellow cards to one by the Ospreys.

Steve Tandy, the Ospreys coach, reckons it will take five wins to win the Pool and guarantee a quarter-final slot. Next weekend's game at Welford Road against Leicester Tigers will be crucial, while Treviso will have to pick themselves up for hosting French champions Toulouse.