"Credit to (Bulls coach) John (Mitchell) and his team they played really well and there's some x-factor speed in their backline."
After imploring his squad to play smarter in the build up to the match, Cooper saw some glimpses of that in the second period with the Chiefs controlling the ball much better and committing fewer penalties.
In the first half, the Chiefs had conceded nine penalties to two. At the end of the match, they still had a higher count, but only gave away three in the second period.
"When we put phases together we looked quite good, so there are a lot of positives out there."
With their resources stretched, the Chiefs pack put in a big effort to lead the comeback, with lock Brodie Retallick playing a dominant part in the match, scoring two tries.
"You can see why the Chiefs, All Blacks and New Zealand Rugby work so hard to not just keep him in the country but to manage him, really take no risks with him, because that's the sort of performance you get from him," Cooper said of Retallick's impact on the game.
Tighthead prop Angus Ta'avao also put on a strong showing, playing the full 80, while fellow front-rower prop Jeff Thwaites, who was in line to make his Super Rugby debut off the bench, wasn't called upon.
It was a precautionary measure from the Chiefs ahead of their trip to face the Sunwolves next week with the front row stocks riddled by injury.
"We kept him in cotton wool really."