John Hartson believes Celtic are currently being sent a warning by Philippe Clement and he reckons his former side must take it on board.

Rangers won the League Cup at the weekend as they defeated Aberdeen and the Ibrox club now have their sights set on a title battle with Celtic as well as the Europa League knockout stages.

Hartson has been hugely impressed by the impact of Clement in Glasgow, but he feels his former side Celtic can take the pressure on board to pull through their current slump in form.

Speaking to Go Radio, Hartson said: “Clement has done a really good job since he’s come in, there is no going away from that. He’s set out to the players what he needs from them, what he’s asking from them - he wants discipline, hard work and commitment. He’s certainly got that in the run of games they’ve been on.

“They’ve shown good spirit, they’ve come back from being behind late in games so they have that spirit and character within the team.

“But can he go on and push Celtic? Celtic need a little bit of help, they’ve had a couple of injuries. But take nothing away from the job Clement has done in a short space of time. He’s won a trophy, and when Clement is talking about titles maybe he is saying not this season.

“If that is not a warning sign for Celtic when the opposition manager is pointing out that he may win titles and wants to win them, you’ve got to respond to that. You’ve got to react to that.

“You’ve got to say ‘while I’m manager here, no you won’t. I’m going to make sure I’m going to the board, I’m going to bring in the right players to suit the club and to suit the way I want to play, and I’m going to get them onto the pitch and I’m going to stop you from winning titles’. That’s what Brendan Rodgers will be thinking."