Martin O'Neill stressed he was stepping into the Celtic hotseat on a short-term basis after admitting shock over his return to Glasgow.
The 73-year-old will take charge on an interim basis alongside former player Shaun Maloney following Brendan Rodgers’ sudden departure.
Celtic announced on Monday night that Rodgers had "tendered his resignation", while principal shareholder Dermot Desmond delivered a scathing statement, accusing the 52-year-old of stoking division.
Rodgers won 11 trophies over two spells but leaves with Celtic eight points adrift of William Hill Premiership leaders Hearts ahead of Wednesday’s fixtures, which see Falkirk visit Parkhead.
O’Neill revealed on TalkSPORT that he had been "shocked" to receive a call from Desmond on Monday offering him a job.
The former Republic of Ireland manager, who won seven trophies in five years at Celtic Park, added: "I took a gasp of breath and thought 'Is this real or surreal'?
"So it’s difficult really to turn down somebody who gave you the job in the first place when he had really some great options a way back 25 years ago.
"So from that viewpoint, maybe by the time that I pulled myself off the floor, I probably thought then maybe I should do it.
"Interim does mean that to me. Absolutely. It’s really as simple as that. Celtic are looking for – I would have assumed – a young coach who has a proven ability and would be wanting to pull the club forward now.
"That’s how I would view it and I suppose if I was a Celtic fan, I would absolutely see it.
"I had a super time there. It was an absolute privilege to have managed them before. My time had gone. I mean, I can’t emphasise this enough. This is short term until a permanent manager is appointed."
"If we don't win on Wednesday evening, we might have a new manager on Thursday"
O’Neill described his feelings as "nervous excitement" ahead of his dugout return.
"If there is some sort of clapping for me, I’m well aware in this game that lasts about 15 minutes," he said. "At the end of the day, you have to win."
Celtic take on Rangers at Hampden on Sunday in the Premier Sports Cup semi-finals and then play Midtjylland in Denmark in the Europa League before hosting Kilmarnock ahead of the international break.
When asked about the timescale, O’Neill said: "I have to win football matches and that’s no different and at Celtic, it’s always been the case.
"If we can win some football matches and give us a bit of buying time as it were, until a new man is appointed.
"They could have a new manager in two weeks' time. If we don't win on Wednesday evening, we might have a new manager on Thursday.
"So I don’t know, and that’s not great news for Shaun to hear, because he was hoping I’d be around for a month.
"Celtic will be looking for a young manager to come in with a very, very decent CV."
Maloney returned to Celtic in June as player pathways manager and his appointment appears to have spelled the end of assistant manager John Kennedy’s time at the club.
The former Celtic defender had a three-month spell in interim charge in 2021 and has worked with the first team since 2014 but was not mentioned in the club’s statement on Monday night.
O’Neill said: "Shaun and I go back years and years, when he was a young player with me.
"But he is experienced in management now and he’s worked as well too with lots of really good coaches I will obviously need help and Shaun is there to give it to me."
The acrimonious nature of Desmond's statement lifted the lid on the extent of the internal strife that had lingered at Celtic throughout a summer when they did not meet their objectives in the transfer market and failed to qualify for the Champions League.
Rodgers had publicly called for more attacking reinforcements and Desmond expressed "deep disappointment" with the former Liverpool boss.
Desmond claimed Rodgers had misrepresented the situation over his own contract talks and that the manager had "full knowledge, approval, and endorsement" over all transfers,
He added that Rodgers’ words and actions had been "divisive, misleading, and self-serving", contributed to a "toxic atmosphere" around the club and "fuelled hostility" towards the board.
Celtic fan groups have vowed to step up their campaign to remove key directors in the wake of Rodgers' departure, laying the blame for the club’s "crisis" squarely on the board.
A pre-match protest is planned ahead of Wednesday’s game against Falkirk by the Celtic Fans Collective, an umbrella group formed following discontent over summer transfer business and failure to qualify for the Champions League.
Danny Rohl has also reacted to O'Neill's suggestion that his side are too far back to be involved in the title race.
Rohl, who took up the Rangers role following Russell Martin's sacking after just 17 games in charge, insists there is belief in the Rangers camp.
O’Neill, in his role as a talkSPORT pundit, declared that Rangers, who are five points behind Celtic following their 3-1 win over Kilmarnock on Sunday "are no threat whatsoever, although the new manager (Rohl), I think he can maybe do something in time. But they are so far adrift, it’s untrue."
Ahead of the trip to Hibernian on Wednesday night, 36-year-old Rohl, who took over from Martin at the start of last week and began with a 3-0 Europa league defeat by Brann last Thursday night, was informed of his new rival’s remarks and said: "I must say this morning, I sat here and looked to the faces of my players and I see there’s a big, big belief now.
"I think they feel it on the pitch. I have the feeling they believe at the moment in what we are doing, in the last days."
Later on Tuesday, O'Neill said "I stand by everything I said. Although if I’d known I was going to get the job here, I wouldn’t have said anything. But that’s the nature of the game.
"Hearts are very strong. They’re going brilliantly at this minute. They’ve opened up an eight-point gap.
"And Celtic, it’s something that I’ve thought about for quite some considerable time. Now, there’s different ways of playing the game. I inherited, about 25 years ago, some really great players, and in terms of adding to that, I think I did.
"And eventually over a relatively short period of time, the team gelled and got together. And we were very strong and had lots of good players. And other than a couple of very young lads in the side, proper men in the team.
"And Celtic, I’ve noticed here in the last couple of years, have not got that, but they’ve still been able to win."
