Neil Lennon defended his record in his second spell as Celtic coach on Wednesday after an influential fans' group joined the calls for him to quit.
The Scottish champions' hopes of achieving a record 10th consecutive league title are fading as they trail Glasgow rivals Rangers by 11 points, although Celtic have two games in hand.
A banner held up outside Celtic Park by Ultras section the Green Brigade on Wednesday read: "Save the ten - time to go, Neil".
Lennon took charge of Celtic for a second time in February 2019 when Brendan Rodgers departed for Leicester.
He guided the club to the past two league titles, plus the 2019 Scottish Cup, 2020 League Cup and has led the side to next month's Scottish Cup final.
"Fans are entitled to voice their opinion, whether I agree with it or not is irrelevant, they have put it out there," Lennon said at his pre-match press conference ahead of Thursday's Europa League trip to Sparta Prague.
"It's something that I am not really going to engage with, I've got a job to do here and I think I've done it pretty well since I came back in."
Rangers are off to their best start to a league season in 53 years and Lennon believes Celtic's campaign is being unfairly assessed in comparison.
The Hoops' defeat in the Old Firm derby last month was their only domestic loss this calendar year.
"We have made a better start to the league than we did two years ago when we went on to win the treble," added Lennon.
"We are going through a sticky patch if you want to call it that, all teams do and good teams come out the other end and so do good managers, that's what I firmly believe we will do."
However, Celtic have consistently fallen short in European football under Lennon, failing to qualify for the Champions League for the past two seasons.
A 4-1 home defeat to Sparta three weeks ago was a new low and anything other than a win in the Czech capital will end their run in the Europa League at the group stage.