Alan Stubbs believes former club Celtic will struggle in the Champions League as their defence isn’t good enough to play at that level.

Celtic reached the group stage after completing an 8-4 aggregate success over Astana, but Stubbs says the Scottish Premiership champions are set for a tough time in the competition proper.

“The only top-class defender they’ve got is (Kieran) Tierney,” Stubbs told the BBC.

“Domestically, (Erik) Sviatchenko, (Dedryck) Boyata, (Jozo) Simunovic are competent, but the Champions League is a whole new ball game.

“In the Champions League you need to allow Tierney to go forward, and that puts extra pressure on the two centre-backs and the opposite full-back. That’s where the problem lies within.

“Last year when they went into the group stage, people thought they just needed to be competitive and do themselves justice – I don’t think anyone thought they were going to come through that tough group.

“But the mindset’s changed now, people are potentially looking for Celtic to progress, to see whether that’s a measure of Brendan improving in Europe, and to do that, I don’t think they’re good enough, apart from Tierney – I really don’t.

“That’s the biggest area of the team when they go to the Champions League they need to improve.”