The home side failed to muster a meaningful attempt on goal as they were beaten convincingly -4-0 - and the Yorkshire side's day was compounded by the sending-off of debutant Dale Jennings.
"I thought Wigan were devastating," Flitcroft said. "I thought up to the goal going in, we probably had our best spell. I thought we gave them some problems for 10 or 15 minutes of the first half, I really did.
"It was quite a competitive first half and we had a bit of possession, but once the first goal went in we struggled to come to terms with that.
"The second goal after half-time deflated the team and then when Dale (Jennings) was sent off then you're chasing Wigan with 10 men, and it hurts at times watching your team having to endure that.
"I don't think as a group they deserved that to happen to them, but it did and we'll grow strong from it.
"We've been well-beaten but there are still a lot of points to play for.
"I think Wigan have put a bit of a benchmark down today and I've told the players if you want to emulate that, then there's a lot more work we've got to do together, and we'll continue to do that."