Celtic manager Neil Lennon said he was delighted after his side beat Rangers 1-0, but revealed he had doubts over his future earlier in the season.
Back on 5 November, Celtic trailed Rangers by 15 points, but Wednesday's victory means they now top the table.
"I was doubting my own position and I'm sure a lot of fans were as well," the Parkhead boss told BBC Scotland.
"But I kept believing in the players and we've turned it around, although there is still a long way to go."
Joe Ledley's header on 52 minutes made it nine wins in a row for Lennon's men and gives them a two-point lead over their Old Firm rivals.
"It was the best Christmas and New Year I could have asked for," added Lennon. "I'm so proud of the players.
"Without being brilliant, it was a very good performance against a dogged Rangers side.
"Rangers are a very good side and that gets overlooked in all the criticism that surrounds both teams at times.
"This Rangers side have been at the top for the last three or four years and have a great mentality."
The visitors had two close-range chances in the first half, with keeper Fraser Forster saving from Lee Wallace and Carlos Bocanegra failing to find the target.
Wallace's effort appeared to have crossed the line but Lennon was not convinced.
"It may have gone over the line but I'm not so sure," he said.
"And I thought Gary Hooper was onside when he was given offside one-on-one with the keeper."
Celtic dominated after the interval, with Rangers seldom seen as an attacking force.
"I thought the control was good, especially in the second half," added Lennon.
"We didn't pass it quickly enough in the first half and I didn't think there was much in the game.
"It was always going to take a goal to settle either team and thankfully we got it."
Lennon was delighted to keep his side's winning run going and to exact revenge for a reverse at Ibrox in September.
"I've been waiting for three months for this game because the 4-2 defeat really hurt me," Lennon continued.
"I wanted a response and I got that tonight.
"The important thing was to win, make it nine in a row and I want to take it on to 10 now.
"Psychologically, it will do the players the world of good.
"And it gives the punters a sense of pride going into the new year.
"I don't enjoy the build-up to these games. It's been over Christmas and it's not been what it should be because you've got this huge game in the back of your mind."