That's better from Sebastian Tounekti, driving to the byeline and smashing in a dangerous cross that's held well by the keeper.

Besiktas jump on Callum McGregor and they've won the ball in the Celtic half. The move ends with Leandro Trossard bending just wide of the far post. They get away with that there, the hosts.

Sam Johnstone has a shot to save within a minute or so of the restart. It's easy enough for the Celtic goalie.

Let's see if this gets any better, then.

Tom English
BBC Scotland's chief sports writer on Sportsound

The first half has been terrible - awful and passive. I think Celtic are working hard but there is no inspiration.

You don't get the sense from Celtic that they're up for a fight. It's just so poor.

It's more of the same for Celtic. The problem for them is that Besiktas can find another level.

Image source, SNS

Hearts head coach Wouter Vrancken tells BBC Scotland: "Just not good enough. There are circumstances, but we expected more from ourselves. Obviously disappointed.

"Individual mistakes are always something that can happen because you are working with human beings. You have to find the energy again.

"The quality was not top today. We don't have to find excuses because the performance was not good enough. You have to adapt to the pitch.

"[Stephen Kingsley] wanted to play. This game was important and it's always a risk. It's also a risk playing players who have played six or seven games in a row with two days in between. This is the situation we are in.

"We have to cope with the situation we are in. There is nobody fit enough now [to return against Falkirk]. It will be the guys who were here tonight. There is a big chance we keep Matthew [Gillies] with us."

I'm going to head to the vending machine to help me recover from that half of football.

In the meantime, here's some reaction from Thun, where Hearts were well beaten earlier.

Safe to say Wouter Vrancken isn't a happy bunny.

Thomas Duncan
BBC Sport Scotland at Celtic Park

Is it harsh to say the intensity of that game was a bit Europa League-ish?

Besiktas don't need the win, and Celtic are lacking confidence on the ball.

Forty-five minutes we won't get back.

Not one shot on target in an uneventful half of Europa League football.

Image source, SNS

Sums up Celtic's half, that.

Total fresh-air swipe in the Besiktas box from Benjamin Nygren and he slips on his backside. Laurel and Hardy stuff.

Image source, SNS

Yup, zero shots on target for Celtic. Zero for both teams actually.

Pat Bonner
Former Celtic goalkeeper on BBC Sportsound

Celtic need to get in at half-time and try and sort this out because this isn't like a Celtic team at home. They haven't tested the goalkeeper at all.

Could count on one hand the amount of times Celtic have actually been able to progress the ball from their half to the other without losing it.

A break looks like it's going to open up for Celtic, but Sebastian Tounekti is swarmed by three Besiktas bodies and the attack ends.

Liam Scales gets away with a shirt pull on Oh Hyeon-gyu, who briefly stops his complaints to block the Celtic defender's attempted clearance. Some boos from the home fans follow.

Tom English
BBC Scotland's chief sports writer

Celtic have had two touches in the Besiktas penalty box. Two.

Liam Scales looks for Sebastian Tounekti up the left, but the Celtic man was always second favourite.

Johan Mjallby has just labelled the winger "a bit lightweight".

Thomas Duncan
BBC Sport Scotland at Celtic Park

Image source, SNS

On that, Nick. Besiktas have had 66% possession over the past 15 minutes.

Celtic need to try to hang on to the ball.