Zenit bring on teenager Kirill Kravtsov for Daler Kuzyaev.

Edouard Mendy is getting some treatment. He was clattered by the big Russian striker there.

Zenit are so close to being level against the run of play.

Sardar Azmoun rolls the ball across the six-yard box and Artem Dzyuba - on the stretch - stabs the ball straight at Edouard Mendy from close range. If he'd been a couple of inches nearer goal that would have been 1-1.

Image source, Getty Images

Marcos Alonso almost wraps this game up. He gets the ball on the edge of the box, shuffles back onto ol' lefty but then drags his shot wide.

Villarreal have come from 1-0 down to lead Atalanta 2-1.

Bayern aren't really breaking sweat here. I can't remember ever seeing a Barca team quite so lost, quite so unable to throw a meaningful punch.

Kai Havertz plays a lovely through ball to Romelu Lukaku. He could shoot but instead cuts back to try to find a team-mate... and he should have shot.

Richard H: People used to say Azpilicueta didn't offer much going forward but he was fantastic defensively... but he seems to get a pretty decent number of assists. Morata would never have scored any goals for Chelsea without him and Lukaku is now reaping a similar bounty

Zenit bring on Russia internationals Artem Dzyuba - who seems to be in every major tournament - and Aleksandr Erokhin for Brazilians Wendel and Malcom.

Only Bruno Fernandes (17), Erling Braut Haaland (20) and Robert Lewandowski (21) have scored more major European goals since Romelu Lukaku left Manchester United than the Belgian (14).

Mateo Kovacic has a shot blocked as Chelsea put the pressure on. Zenit are getting some subs ready.

Chelsea push for a second. Zenit have been happy to sit in but they'll have to take risks and leave some spaces at the back surely.

Lee Dixon
Former Arsenal and England defender on BBC Radio 5 Live

Lukaku has been the one, a real threat to the three centre-backs. On this occasion he gets close enough to the goal.

Azpilicueta puts a great ball in, right where Lukaku wants it - he doesn't have to move. He just waits and times his jump to perfection, superb header.

Image source, Getty Images

Philippe Coutinho curls an effort from range over the bar. Well, it's something.

Chelsea have had many more attacks than Zenit, and yet Blues keeper Edouard Mendy has had to make more saves. This is actually a simple catch from Wendel's 18-yard curler.

Ronald Koeman has to do something. He sends on Yusuf Demir for Sergi Roberto and Gavi for Sergio Busquets.

Not long after, Philippe Coutinho and Oscar Mingueza join the action.

All dice thrown.

I've rarely seen a goalkeeper look so unconvincing from crosses... and yet be successful on dealing with every one. Stanislav Kritsyuk again parries this corner away.

Mason Mount wins the ball well and finds Kai Havertz, who is tackled well in the box by Yaroslav Rakitskiy.

From that corner, Chelsea eventually win another one.

It must be especially galling for the likes of Jordi Alba, Gerard Pique and Sergio Busquets to experience this. They are players who have played in so many of the kind of dominant Barca displays that the Catalan side are on the receiving end of here.