Celtic places at risk, warns Craig Gordon after Anderlecht defeat
Celtic players realise they need to improve on the European stage despite reaching their Champions League target, says goalkeeper Craig Gordon.
The Scottish champions ended their Group B campaign with a disappointing home defeat to Anderlecht.
But one win was enough to take them into the Europa League round of 32.
"We have to be performing at the highest level, if not, at a club of this size, then you run the risk of being replaced," said Gordon.
"We need to do as well as we can in these big games to try and stay in the team.
"I'm sure the manager will be looking to strengthen the squad again in January."
Anderlecht, who had lost all five matches before Tuesday's trip to Celtic Park, needed to equal the 3-0 loss they suffered against Brendan Rodgers' side in September to claim third place behind Paris St-Germain and Bayern Munich.
Following the 1-0 loss to the Belgian side in Glasgow, Rodgers said it was a "reality check" for his team.
"For some of our players this was a good game because some of them think they're Champions League players," he said. "So this is a good level for some of those guys to reflect on their performance."
Gordon was one of Celtic better performers, making a great early save to deny Sven Kums.
Looking forward to the Europa League, the Scotland keeper said: "We will have to play better, especially at home, to give ourselves the opportunity to win a knock-out tie.
"And, defensively, we will need to be good on our travels. We've still got a lot to learn from this group.
"The bigger picture is that we were fourth seeds going into the group and we've finished third.
"That's a reasonable achievement; we wanted European football after Christmas.
"It always looked like a shoot-out between us and Anderlecht for third and with PSG and Bayern for the top two places. That's what everyone expected and that's how it turned out.
"You very rarely get a shock with one of the smaller teams going through. But, on the night, we wanted to play better. We wanted the win.
"It was almost like a knock-out tie, with a 3-0 lead from the first leg, so we had that mind.
"We didn't pass the ball as well as we normally would; we didn't have as much control. Against a team like Anderlecht at home we would expect to have more of the ball.
"Circumstances dictated that we wanted to protect what we had and we were more cautious.
"We'll be happy with it eventually but we are a little bit disappointed in our performance."