Second-half tries from Cory Allen, Dan Fish (2) and Lloyd Williams brought them to within a score at one stage, and the resulting bonus point keeps their hopes of qualification alive even if they will rely on results elsewhere on the final weekend.
And Wilson admits his side's lack of fast starts in games has cost them, both in Europe and the GUINNESS PRO12 - where they sit ninth in the standings.
"We have shown we need to be put away. We fight until the end and this group of players keep fighting and fighting," Wilson told Cardiff Blues' website.
"I don't know how many comebacks that has been now - obviously we need to improve our starts. We do show plenty of spirit and plenty of fight for the jersey and each other.
"Unfortunately a couple of set pieces with a very young front row at the end have cost us two bonus points, but I can only be positive about that second half performance.
"It was a game of two halves. The first half we stood off a little bit defensively and allowed them to run at us. You can't allow them to do that with the power runners they have got.
"In the second half we held onto the ball and managed to score. We got four great tries and won the second half 26-6. To come away from home, to a side like Harlequins, and do that, these boys should be proud of that."
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