McCann acknowledged that Oxford United would not have deserved to lose, a fate they faced when Alfie May netted from close range on 90 minutes for the hosts in a game in which they had largely been second best.
“We took the one chance we had, so we showed some ruthlessness. Then we just switched off and (Josh) Ruffels scores, swinging it off the post,” said McCann.
“It’s the first time it’s happened to us this season. Maybe we thought the game was won and that was the frustrating thing.”
McCann was quick to raise the spirits of his dejected players.
“I’ve said to the group not to let it dent their confidence or stop their momentum and we’ll go again,” said Rovers’ boss.
McCann elected to praise Oxford rather than be critical of Rovers’ players, saying Karl Robinson’s side are the best to have visited the Keepmoat this season.
“I knew Oxford were a good team, they’re the best team we’ve played at home this season,” he said. “I won’t criticise my boys because Oxford were really good. The boys tried to do what they do normally, but it didn’t come off.”
Ben Whiteman had put Doncaster ahead with a 20th-minute penalty, but a short free-kick routine from Oxford on 64 minutes fooled Rovers’ defence and Gavin Whyte netted Oxford’s first equaliser.
Doncaster Rovers: Lawlor, Cummings (Blair 75), Tom Anderson, Butler, Andrew, Crawford (Rowe 73), Whiteman, Kane, Coppinger (May 84), Marquis, Wilks. Unused substitutes: Marosi, Taylor, Amos, Blaney.
Oxford United : Eastwood, Hanson, Nelson, Dickie, Ruffels, Henry, Mousinho, Brannagan, Whyte, Mackie (Garbutt 88), Browne. Unused substitutes: Smith, Raglan, Long, McMahon, Little, Mitchell.
Referee: Alan Young (Cambridgeshire).