Zenit subs: Kerzhakov, Odoevski, Krugovoi, Mostovoy, Erokhin, Dzyuba, Kravstov, Khotulev.
Zenit starting XI: Kritsyuk, Sutormin, Chistiakov, Rakitskyy, Douglas Santos, Malcom, Wendel, Barrios, Kuzyaev, Claudinho, Azmoun.
Chelsea subs: Kepa, Bergstrom, Silva, Werner, Loftus-Cheek, Chalobah, Saul Niguez, Barkley, Hudson-Odoi, Chilwell, Havertz, Sarr.
Chelsea starting XI: Mendy, James, Azpilicueta, Christensen, Rudiger, Alonso, Kovacic, Jorginho, Mount, Ziyech, Lukaku.
Stat: Zenit have lost each of their last three trips to England - most recently against Liverpool in February 2013 in the UEFA Europa League.
Stat: In UEFA Champions League history, the reigning champions have only lost their first game of the following campaign on two of 27 occasions (AC Milan in 1994-95 and Liverpool in 2019-20).
Stat: Zenit Saint Petersburg are winless in their last seven UEFA Champions League games (D1 L6) - their longest run without a victory in their history in the European Cup/UEFA Champions League. Indeed, they failed to win all six of their group stage games in the competition last season (D1 L5).
Stat: This will be the first meeting between Chelsea and Zenit Saint Petersburg in European competition, while the Blues are unbeaten in six previous games against Russian sides in the UEFA Champions League (W5 D1).
Chelsea team news: N'Golo Kante will miss out with continued ankle trouble but is expected fit for Sunday's Premier League trip to Tottenham, while Christian Pulisic is still sidelined with his own ankle problem.
Hello and welcome to our live coverage of Chelsea vs Zenit in the UEFA Champions League. The match is being played at Stamford Bridge and kicks off at 7.45pm UK time.
Chelsea nearly give the ball away near their own box twice in the first minute. A sloppy start by the European Champions.
We are underway at Stamford Bridge!
Malcolm tries to take on Rudiger down the right and gets shoved aside. That's very strong defending by the German.
Chelsea are dominating possession so far but Zenit are resolute and not giving much space.
Alonso and Mount try to link down the right but Zenit are very strong defensively with Sutormin tackling strongly.
Claudinho is making his Champions League debut tonight for Zenit and is looking lively by finding space behind Jorginho.
Close! Rakitskyy plays a lovely pass over the top for Azmoun but Christensen makes a crucial headed clearance for Chelsea.
CHANCE! Azmoun beats Azpilicueta in the air and it reaches Claudinho at the back post for Zenit. James recovers quickly and makes a potentially goal saving challenge.
Zenit have left Dzyuba on he bench tonight and are playing with one striker.
Block! Mount finds Ziyech to turn and shoot on the edge of the box but Zenit are out quickly to block.
Kuzyaev makes a good run down the right for Zenit but Kovacic tracks him well and slides in to win a tackle.
Chelsea break but Mount can't quite find an angle to Lukaku. When he does eventually play a killer ball, it's too heavy for James.
Jorginho concedes a freekick on Claudinho. Zenit work it out to the left and it reaches Kuzyaev to shoot from 30 yards but high and wide of Mendy's goal.
Chelsea aren't quite at it so far tonight and that's credit to Zenit who are moving the ball really well and defending solidly. They've arguably been the slightly better side.
The hosts finally work the ball nicely to Lukaku via Mount and the Belgian nearly bundles his way through but Rakitskyy comes across to make a good tackle in the box.
James takes a corner from the left for Chelsea and Kritsyuk does well to punch clear in the Zenit goal despite taking a knock as he does so.
Chelsea have had 63% possession so far but haven't done that much with it.
Kovacic makes a nice turn in midfield and finds the feet of Ziyech but he is well challenged by Barrios before he can get a shot away. It's been a slow start to the match for the Moroccan.
It's been toothless from Chelsea so far. Zenit allowing the ball to go to Alonso and keeping the centre well blocked up.
The Blues step it up somewhat as play is switched to James. He goes around his man but his cross is blocked well. That sums up the evening so far.
Mount comes to life and bursts past a couple of challenges well. He slips it to Lukaku on the left and the striker has shot a blocked. Zenit's defenders are really up for the fight tonight.
Chelsea win a corner as Mount turns and releases Alonso to cross on the left. James delivers an inswinger from the left but it fails to beat the first man.
There are more misplaced passes as Mount gives it away on two occasions. Thomas Tuchel won't be happy with his team's showing so far.
Claudinho wins a corner off Jorginho. Zenit take it short and work it to Rakitskyy at the back post and his curling shot brings a rudimentary save out of Mendy.
Rudiger plays a diagonal for James which Santos heads behind. Ziyech delivers the corner from the right side and Kritsyuk has to parry it clear under severe pressure. Good goalkeeping there.
Another corner to Chelsea after Lukaku tried to tee up Ziyech. The latter takes it and it misses everyone as Kritsyuk struggles to deal with it. The Zenit 'keeper is looking very dodgy at dealing with these corners.
Over! James delivers a cross into the area but Chistiakov is very tight to Lukaku and forces the striker to head wide of goal under pressure. A decent half chance.
HALF TIME. No shots on target for the hosts because of a rock solid display by their Russian opponents. Chelsea 0-0 Zenit. Join us in 15 minutes for the second half.
Yellow! Azpilicueta is carded for catching Azmoun in the face as they challenge for a high ball.
Kovacic does well and releases Mount away down the left wing but the midfielder's left footed cross is poor and it missed Lukaku's run by a distance.
The second half is underway.
Chelsea have started this second half a bit sharper with quicker ball movement. Mount has a shot saved by Kritsyuk.
CLOSE! Rudiger embarks on a 50 yard sprint with the ball, goes past a couple of Zenit players, beats a man in the box but fires his shot just wide of the post. What a run by the centre back.
Alonso gets a low cross into the Zenit box towards Lukaku but Chistiakov does well and blocks the striker's effort and also wins a goalkick. Good defending.
Malcolm goes past Alonso and Christensen has to concede a corner. Zenit go short but they make a complete mess of the set-piece.
Ziyech makes a nice turn in the box but he can't find Lukaku's run inside the area. But Chelsea are looking quicker and more inventive in this second period.
Side netting! Lukaku holds the ball up well but James goes with his left foot and can only hit the side netting for Chelsea.
Mount overhits another pass which is too hard for Alonso and goes out for a throw-in. It's been that kind of evening for the Englishman.
Goal saving tackle! Azmoun gets into the area and goalside of Azpilicueta but Rudiger comes across to make a perfectly timed challenge. The German celebrates his own top defending. Zenit will fancy their chances of nicking a win here.
Yellow! Mount makes a lovely run and is chopped down by Rakitskyy. The referee issues a caution.
Sub for Chelsea - Ziyech goes off after a poor performance with Havertz coming on.
Alonso curls a freekick into the box, Havertz nearly gets there and it falls for Kovacic to swipe a shot a long way wide. Will Chelsea find a goal here tonight?
Mount wins a crunching challenge and releases Havertz to win a corner off Rakitskyy. Alonso goes across to take it from the right... easily cleared.
GOAL, CHELSEA! LUKAKU! There is the goal finally. Azpilicueta delivers a superb cross and Lukaku gets up highest to head home. A lovely assist and finish. Chelsea 1-0 Zenit.
Now Wendel cuts inside for Zenit and draws a save out of a well positioned Mendy. The visitors still carry a threat.
Mount twists and turns in the area but Zenit crowd him out. The Blues want a second goal here.
A long spell of Blues pressure comes to nothing as Mount's cross is too floated and is easily caught. He was looking for Lukaku.
Subs for Zenit: Malcolm off for striker Dzyuba and Wendel goes off for Erokhin.
Just wide! Chelsea patiently move the ball around and Mount finds Alonso who gets it onto his left foot and fires across goal but wide of the upright.
CHANCE! Zenit should level it up. Azmoun gets in-behind down the right and squares across the face for Dzyuba but he puts it wide with Mendy throwing himself the striker. That's a huge miss.
Mendy is getting some treatment after taking Azmoun's studs in the chest.
Subs for Chelsea as Thiago Silva replaces Azpilicueta and Chilwell comes on for Alonso.
Sub for Zenit: Kuzyaev for Kravtsov.
Zenit are having a long spell of possession now which Chelsea are allowing to some degree. 1-0 is enough for the hosts.
Double sub for Zenit: Mostovoy for Claudinho and Krugovoi for Rakitskyy.
FULL TIME. Chelsea 1-0 Zenit. A very tough evening but Lukaku's goal separates the sides with his header after 69 minutes. Thanks for joining us tonight.
+4 James commits a foul. Late freekick for Zenit. Chelsea break at pace but Lukaku goes alone with three players in support.
+3 Sub for Chelsea: Loftus-Cheek on for Mount for the closing stages.
+2 Chelsea keep the ball for two full minutes to take the string out of things.
The fourth official indicates four minutes of additional time to be played.