But Glasgow ran another three past the reigning Magners League champions.
Nikki Walker would have impressed Scotland boss Andy Robinson ahead of the autumn internationals with a scintillating hat-trick, but it went to waste as Glasgow hit back with two late tries to steal a victory.
And Holley was bitterly disappointed to leave Firhill empty handed after leading 16-11 at half-time
"I'm a bit frustrated and angry," said Holley.
"I'm disappointed we've scored three tries away from home yet come away with nothing.
"What is even more disappointing is that we conceded three sloppy tries after only conceding four in total in our Magners League campaign up to this game.
"We slipped off too many tackles and allowed Glasgow too much field position.
"We have a bit to work on this week. Our discipline was an issue in the second half and we didn't get our hands on the ball enough.
"But all credit to Glasgow. I thought it was only a matter of time until they kicked off their season and they did it against the Ospreys.
"But we have a strong squad. The boys will have to pick up the pieces and front up against the Dragons next week."