Rovers ran out comfortable 3-0 winners to boost their cushion inside the top six to four points while still holding a game in hand.
McCann confessed to worrying about the game as he travelled to the Keepmoat on Tuesday, concerned Sunday's FA Cup tie with Premier League Crystal Palace may be a distraction.
And he said he quickly apologised to his players after they returned to the changing room.
"It's easy to get distracted," McCann said.
"It's such a big game coming up on Sunday and it's so easy to get distracted from anything, from the league.
"I don't think we did that.
"I apologised to the group because I told them what I was thinking before the game.
"Hopefully I didn't show them that at the time. I spoke to my staff and I didn't.
"It was just a deep thing inside of me as I was driving up. I felt a wee bit concerned.
"I shouldn't have done.
"They're a tremendous group. Their mindset and mentality to win a game is outstanding."
McCann said the build-up to the game had worried him but said the players had gone up in his estimation in terms of their mentality.
And he believes winning the game in hand will have delivered a considerable boost to all at the club.
“I sensed a few things during the week,” McCann said. “I don’t really want to go into it but I sensed things – not with the players – just a few things.
“I thought there might have been a bit of mis-focus on the game which is now how I live, it’s not the way I work and the way these players work, obviously.
“We’re pleased to get the three points and I think psychologically it was a massive boost for us.”