Now the Welsh region know they will have to raise their game for next Sunday's European opener against Leicester Tigers at Welford Road.
Holley said: "Clearly there are elements there for us to work on and perhaps it's quite timely as well.
"I'm glad we've had a significant test because having beaten Ulster 43-0 and won twice away from home, some people start to believe their own press.
"We were well tested and we are quietly happy about that as coaches. We make no excuses. It leaves us with some selection headaches and things to work on, which is a positive.
"Next week's a different game and a different occasion. You will see a different team, both on the team-sheet and in playing terms."