Ange Postecoglou admits Celtic were far from at their best against Dundee United.
And he's demanded his stars up their game as they move to within two points of leaders Rangers thanks to Liel Abada's late strike.
The Hoops went into the Parkhead clash knowing a win would put the heat on the league leaders after they'd dropped points at Ross County earlier in the day.
But with ten minutes to go, it looked as if they'd blown it with Nir Bitton's red card leaving them a man light.
However Postecoglou 's team rallied and found a winner thanks to Abada's clinical finish.
And it means they can now go top of the league with a victory against their bitter rivals on Wednesday night.
Postecoglou said: "Our performance wasn't the best tonight, especially in the first half.
"I thought we lacked energy and intensity, although we still created chances and second half we probably created enough chances to win the game.
"As the game goes on there will be anxiety there and we got a man sent off. But these players refuse to give in, they find a way to win when they need to and they did that tonight.
"From that point of view, it was outstanding."
It was the second time this season Celtic had won a game with fewer men on the park than the opposition as they did so in Dingwall earlier in the season.
He reckons that shows his side have the mentality when things are going against them and he says that's credit to the players, and not himself.
"It's good because they're prepared to roll their sleeves up when things aren't going our way," he went on.
"Rather than get frustrated and lose our composure, they just keep going to the final whistle."
Postecoglou knows his team have the chance to put themselves in the Premiership driving seat by beating Rangers at Celtic Park on Wednesday.
But he insists nothing will be won either way this week as he's urged his side to keep his eyes on the prize.
"We've just got to keep doing what we're doing and we've got to play better than we did tonight.
"We need to keep our focus on the football we want to play. We understand that winning on Wednesday night gets us into first place but it doesn't get us a trophy.
"Until we get a trophy in our hands we can't stop. I thought the fans were outstanding tonight, it's easy for them to get on the players' backs but they kept willing them on and we're going to need them on Wednesday night."
