The Stags were ahead for a long time when Danny Rose broke the deadlock on 26 minutes and had further chances to extend their lead before George Maris levelled for the hosts two minutes from time.
He said: “We were resolute for 88 minutes and we’ve decided not to close that line of the ball down.
“It’s a moment you look at on 88 minutes, if we could have had a bit more drive to close the ball down then he doesn’t get a clean shot. But he got a clean shot.
“When you break it down as to why they possessed so much dominance in the second half it was clear that in the critical moments in transition we gave the ball up. We were loose. We didn’t care enough to protect the ball.
“Up to scoring and just after we looked a very good team. We looked in control and looked to dominate. The style of play was there. We really deserved the goal and coming here it was really quiet.
“I think, with the form of Cambridge, the supporters are probably thinking here we go again. But we didn’t ride that. If you’re going to be ruthless and take all three points then it’s important that in those moments you stick it to them and make sure there’s no coming back from it.
“Second half there wasn’t enough bravery to get on the ball to dictate and dominate play. We gave the ball up too much again for them to throw it down our throat.”
And, speaking of the last 30 minutes, added: “Because they committed so many forward we had open space.
“But we gave them the ball back. We didn’t threaten them enough. We didn’t hurt them enough. Really good counter attack opportunities that we let slip by. It was a day where it seemed OK to let things go by.
“It’s not good enough when you’re in the league, you’re winning and you’ve got something to really hold on to. That should galvanise the spirit and we didn’t hold on for long enough.”