An 82nd-minute goal from Kelechi Iheanacho earned Celtic a 2-1 win at Dens Park – two weeks after a 2-0 defeat along the road at Tannadice.

Celtic have lost three times in the City of Discovery this season but started well this time as Yang Hyun-jun finished off an eighth-minute attack.

O’Neill’s side looked like they might pay for a series of missed chances when Simon Murray equalised from the spot following Colby Donovan’s handball, but Iheanacho netted from six yards to move Celtic three points off William Hill Premiership leaders Hearts.

“For the first time, a fortnight ago, I had to question whether we really, really wanted it,” the 74-year-old said.

“Forget about the pitch, just in the second half I felt we didn’t show an appetite to get into the game.

“Then you have a fortnight to think about it so we’ve come in with renewed determination, to try to get in front and take the game away from Dundee. We did that, we’re still in it and still have a lot to ponder.

“Did we reset our attitude? Absolutely, I think we did, and that was to do with the way we approached the game right from the off. We carved out chances.

“When the second goal didn’t come, maybe it’s just the pessimistic side to me, but I felt it might come back to haunt us. They got the penalty, the resurgence of confidence, so it was tough.

“But we had to try to do something because a draw was no good for us.”

It was Iheanacho’s first goal in six months in a season beset by hamstring problems.

“I had a chat with him,” O’Neill said. “He’s a very fine player. At 29 he should be at the peak of his career rather than scratching around. He has played for Manchester City.

“That will do him the world of good. He’s absolutely buzzing in the dressing room.”

A fit and confident Iheanacho could solve a problem for O’Neill, who has not seen a starting centre-forward score in the past 12 games.

Tomas Cvancara started at Dens but squandered a series of opportunities.

“Naturally, he was pretty down after the game,” O’Neill said. “Some of the chances that he had, I think he could have easily had two anyway.

“It becomes frustrating because, no matter what you say, centre-forwards thrive on scoring goals.

“I have been spoiled obviously with centre-forwards here way back years ago.

“A centre-forward’s got to try to hold the ball for a start. Then, naturally, they’ve got to get on the end of things and score some goals.

“But when that’s not happening, then it does cause a problem.”

Dundee manager Steven Pressley said: “I’ve said to the group that they make me exceptionally proud.

“We didn’t come into the game to sit in and absorb pressure. We came to try and impose ourselves on the game, and to do that you’ve got to be brave with and without the ball. I think the players showed that bravery.

“When we got back into the game with the penalty, I felt that we were going to be the team that could go on and win it.”