Former Celtic striker Chris Sutton has questioned defender Cameron Carter-Vickers after his recent displays.

It's been a tricky period for the Scottish club, with inconsistent performances ramping the pressure up on manager Martin O'Neill.

Their displays in Europe have been particularly disappointing, while perhaps being fortunate to have picked up as many points as they have in the league.

There have been many calls for O'Neill to be sacked due to some of the decisions he's made, which is always interesting considering they're still top of the Scottish Premiership.

Their performances in Europe are what will truly define O'Neill's tenure, though, as they are expected to win the majority of the games in the league.

Their recent performance against Falkirk will be a huge cause for concern too, ramping up further pressure on O'Neill.

Speaking live on Sky Sports during the game in the 41st minute, former Celtic striker Sutton had some harsh words to say about Carter-Vickers.

Sutton suggested that he's someone who has had plenty to say for himself recently and that maybe he needs to concentrate on his own game after a disappointing performance.

"He's had plenty to say for himself in recent times. Maybe he needs to concentrate on his own game."

This comes after Carter-Vickers was questioned for speaking out in the media, seemingly slamming either his teammates or the tactics on display.

"You can see that it's a little bit broken in how we want to play, it's a bit nervy and awkward at times," said Carter-Vickers.

Former Celtic midfielder Scott Brown also questioned whether it was right for Carter-Vickers to speak out like he did.

As Sutton mentions, Carter-Vickers should maybe only be speaking out if he's performing to an acceptable level.

Some of Carter-Vickers's displays haven't been good enough to warrant him questioning others, and he should be focusing on himself.

Celtic need to step it up a level

There's no doubt Celtic need to step it up a level after their recent performances in both the Scottish Premiership and in Europe.

Carter-Vickers is far from the only problem at Celtic, and he's certainly not the biggest problem, but he and others need to fix up.

Thankfully for them, Old Firm rivals Rangers haven't quite hit the heights expected of them just yet, meaning they do still have a gap at the top of the table.

They face an incredibly difficult challenge of trying to qualify for the next round of European competition, though, and that's where O'Neill and the players will be truly judged.

There's plenty of time in the season for them to go on a proper run of games in both competitions, but things aren't looking too rosy at the moment.