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.
Ebbw Vale captain Damien Hudd picked up the biggest accolade of the night at the 11th Principality Premiership Awards Evening held at Principality Stadium, after leading his side to the title for the first time.
Wales assistant coach Robin McBryde is predicting a tough battle against England on Sunday despite the fact they may not be considered to be at full strength. Players will be out to impress Eddie Jones which makes England a dangerous proposition, he says.
Wales U20 captain Tom Phillips and performance psychologist Dr Rich Neil explain why spending three days at Monmouth RFC has further strengthened the togetherness of the squad ahead of the #WorldRugbyU20s
Alongside Scarlets flanker James Davies and Cardiff Blues centre Cory Allen, three Wales Sevens core players have made the extended training squad for GB Sevens. Wales Head coach Gareth Williams tells WRU TV's Graeme Gillespie why Luke Treharne, Sam Cross and Luke Morgan earned selection in the initial training squad for Rio.
Wales Sevens head coach Gareth Williams tells WRU TV's Graeme Gillespie he has had to overcome a number of injuries before naming a competitive squad for this weekend's penultimate round of the World Series in Paris.