Not many teams leave Ravenhill with a win, but the second-string Ospreys muscled their way to a 20-12 victory that Holley says is a turning point in their season.
"We didn't start the season well, probably because we were in a new home and we had a lot of injuries to key players, but I think you've seen the real Ospreys in the last couple of weeks," he said. "The win in Ulster was brilliant - we had about a dozen players missing, but the other guys really dug deep. Not many teams will win in Ulster this season and it was a very nice feeling to return with the points."
Holley said the defending champions had no intention of taking their hands off the Celtic League trophy just yet.
"We're about sixth on the table and I think a lot of the top teams will take points off each other. And looking at the draw, about seven of our last 10 games are at home. We know we can't afford to lose too many more games, but it's a bit early to write us off just yet.
"Our next game is the Powergen Cup match against Bristol on December 2, and - touch wood - we should have a full compliment of players back by then. The likes of Gavin Henson and Ryan Jones are targeting that match, and I don't think many teams will be looking forward to playing us when all our players are fit."
Outside-half Shaun Connor - who is enjoying the best season of his career - was again the Ospreys' hero on Friday night. He slotted four penalty goals and a clever dropped goal to compliment the effort of scrum-half Jason Spice, who scored the only try of a hard-fought match.
WRU International Skills Coach Jason Strange is a busy man, combining the new role with that of Wales Under 20 attack coach, Ebbw Vale head coach and continuing to teach at Ebbw Fawr Learning Community.
Warren Gatland and Sam Warburton look ahead to this week's crunch RBS 6 Nations tie against France, where the Wales skipper in particular is keen to make his mark, as Paris has proved a bleak place for him in the past.
Following their historic win over England, Wales Under 20 suffered a narrow, 36-34 loss to their Scottish counterparts last weekend, despite outscoring them by five tries to three. Watch the match highlights and reaction.
WRU TV go behind the scenes with the Wales squad as they put the final touches in place ahead of the clash against Scotland at Murrayfield. Follow the squad on their captain's run, the kickers visit to Murrayfield and Neil Jenkins' press conference