North End dominated the first half but only had Joe Garner's glancing header on the stroke of half-time to show for their efforts as they held a narrow lead.
And the U's made them pay as they missed chance after chance when Luke Garbutt's first league goal for the club earned the visitors a share of the points.
"It was a brave performance," Dunne said. "We dug deep and we had to make changes and I thought in the second half we had a right go.
"They missed a lot of good chances, but that's football. I'm pretty sure that Simon (Grayson) will be disappointed because if you don't take your chances that's what happens.
"It could have been a heavy defeat but I have to pay credit to my players. I told them that we needed to stay in the game at half-time, and we did.
"I spoke to them at half-time about being more basic. We never passed the ball and we had to win more tackles and headers because we just weren't getting around people.
"We managed to control their rhythm more in the second half.
"I took a left-back off to put on a more attacking player and in the end it's played a part in Luke's goal.
"We got an equaliser and there were one or two moments after that when we might have even nicked all three points."
- Sports & Recreation
- Luke Garbutt