Ulster and Ospreys provided a thrilling opener to the Magners League campaign with the Irish province prevailing 27-26 at Ravenhill on Friday night.
The defending champions were 26-24 up with nine minutes remaining when Niall O'Connor scored his fifth penalty of the night to put the home side in front.
In a tense finish both sides had opportunities to score but neither could find the breakthrough with Ulster holding on to justify their status as potential champions.
This proved a tight encounter right from the off with both sides on the scoreboard after 11 minutes - Ospreys taking the lead through a Dan Biggar penalty on four minutes before O'Connor levelled with a penalty seven minutes later.
O'Connor had the opportunity to hand his side the lead on 17 minutes only to send his penalty attempt left of the posts, but Ulster did not have to wait long for their second score of the night.
With just under a quarter of the game gone an error at the lineout from Jerry Collins handed Ulster the opportunity they needed and Ireland international Stephen Ferris crashed over for the game's opening try. O'Connor added the extras to make it 10-3 and just three minutes later the fly-half scored his second penalty of the match.
Biggar replied with a penalty and despite losing Nikki Walker to the sin bin, the Ospreys found themselves back on level terms when Biggar converted Richard Fussell's 29th minute try.
The extra man worked in Ulster's favour as Darren Cave crossed just after the half hour mark but Biggar recorded another penalty to make it 18-16 at the break.
The restart saw O'Connor add to his personal tally but within a minute the visitors were in the lead thanks to some sloppy play. Biggar was on hand to cross for the defending champions and he had little trouble converting to make it 21-23.
O'Connor missed the chance to hand Ulster the lead on 52 minutes but he did not squander the opportunity moments later and a thrilling finish followed.
Biggar responded on the hour mark and after some tense play O'Connor scored his fifth penalty of the night to make it 27-26, which was how the match ended, much to the delight of the Ravenhill faithful.