Martin O’Neill has admitted he will consider his future as Celtic manager after a second defeat to Rangers in the space of eight days.
The 74-year-old said he will reflect on whether he can turn things around at Celtic and plans to speak to the club’s board during the international break.
Celtic were beaten 1-0 by Rangers at Celtic Park on Sunday after Ryan Naderi scored the only goal of the game in the first half.
It followed Rangers’ emphatic 3-0 victory over their Old Firm rivals in the Premier Sports Cup at Ibrox the previous weekend.
Celtic have now suffered three successive defeats, with a 3-1 Europa League loss to Ferencvaros at Celtic Park coming between the two Old Firm games.
O’Neill confirmed after Sunday’s defeat that he intends to use the international break to consider whether he remains the right man to lead the team.
He said: “I will reflect on the games.
“I’ll obviously speak to the board. And you never know, they may want to speak to me. I’ve got some time to do that.
“I will have a look, try and get a couple of days away and see how it goes.”
Asked what would happen if he concluded during that period of reflection that he could no longer improve Celtic, O’Neill left his future open.
He said: “By that time, I will promise you, I’ll let you know.
“I don’t know. I’ll have a look.”
O’Neill also accepted supporters were entitled to question whether he could turn Celtic’s form around.
He said he was “not immune from criticism” and acknowledged there was every reason for questions to be asked about whether he could change the team’s fortunes.
Celtic remain top of the Premiership despite their recent run, although Rangers have now closed the gap to just two points after seven league games.
O’Neill said: “We are two points clear, so I have to kind of look at the bigger picture at this minute.
“But I knew that we were in a big, big fight anyway, with both ourselves, Rangers, and Hearts again, who are far from out of anything.
“It’s a long season ahead. It’s not the first time I’ve been questioned about my managerial time. So, yeah, I’ll have a look at it. I will reflect and see.”
O’Neill returned to Celtic last season and had two spells as interim manager before being appointed on a permanent basis.
He signed a one-year rolling contract in June after guiding Celtic to the Premiership title and Scottish Cup.
His position has now come under increased scrutiny following a damaging eight days in which Celtic have lost twice to Rangers and suffered a home defeat in Europe.
Rangers manager Derek McInnes, meanwhile, said his side’s victory at Celtic Park was thoroughly deserved and believed they could have won by a greater margin.
The result leaves Celtic facing a period of uncertainty during the international break, with O’Neill now openly considering whether he can turn their season around.