Charlie Mulgrew admits Celtic need to improve massively on their display in the 2-1 win over Dundee when they take on Salzburg in the Europa League.
Ronny Deila's side face the Austrians on Thursday, knowing a home win will secure a spot in the knockout phase.
"We'll need to be a lot better than that, we'll need to be 10 times better than that," said Mulgrew after the weekend victory over Dundee.
"We'll do all we can to put in a much better performance."
It was Celtic's first match since the international break, with Mulgrew and captain Scott Brown key figures in Scotland's Celtic Park matches with the Republic of Ireland and England, and goalkeeper Craig Gordon playing the second half of the friendly against the latter.
|Celtic midfielder Charlie Mulgrew|
|"They were a top side so it's going to be a very difficult game. We need to be on our guard and be prepared."|
"We're disappointed with the performance," said Mulgrew after the games against Dundee.
"The main thing is the three points but we want to perform better. There was a lot of tired bodies after the internationals, we've played a lot of games.
"But we're not using excuses, as it wasn't good enough. We got the three points in the end, though."
Salzburg lead Celtic's Europa League group after four matches. The Austrians, with whom have 10 points, two more than the Scots. Dinamo Zagreb have three points and Astra Giurgiu prop up Group D on one.
"It's a good standard, there are no bad teams in the competition," said Mulgrew of the Europa League.
"There are some real quality teams and we saw that when Dinamo Zagreb came here [a 1-0 win for Celtic].
"We are managing to raise our game for it and be up for it, because we know that's what the fans demand. We're doing all we can to get as far as we can.
"They [Salzburg] were a top side so it's going to be a very difficult game. We need to be on our guard and be prepared.
"We're not looking too far ahead."