Slavko Vincic is tonight's referee. His assistants are Tomaz Klancnik and Andraz Kovacic, while Matej Jug is the fourth official and Pawel Gil the VAR.
Both legs of this tie will be played in Spain due to COVID-19 travel restrictions.
Chelsea: Mendy, Azpilicueta, Christensen, Rudiger, James, Chilwell, Kovacic, Jorginho, Mount, Werner, Havertz. Subs: Kepa, Alonso, Kante, Silva, Abraham, Pulisic, Caballero, Giroud, Hudson-Odoi, Zouma, Ziyech, Palmieri.
Porto: Marchesin, Manafa, Mbemba, Pepe, Sanusi, Corona, Grujic, Uribe, Otavio, Marega, Diaz. Subs: Leite, Loum, Ramos, Baro, Joao Mario, Felipe Anderson, Martinez, Evanilson, Nanu, Sarr, Vieira, Conceicao.
Hello and welcome to our live coverage of this UEFA Champions League quarter-final first leg clash between FC Porto and Chelsea at the Ramon Sanchez Pizjuan Stadium.
Chelsea kick off this clash of former European champions. Porto won this tournament in 1987 and 2004, while Chelsea won it in 2012.
Early attack from Chelsea. Havertz flashes a ball across the face of goal, but there's no-one there to finish.
Chelsea have had most of the early possession and orchestrated just about all of the early attacking play.
Corona puts a testing ball into the area from Porto's left, but Mendy is equal to it and holds on.
Uribe controls the ball and looks to volley into the top corner from the edge of the box, but just misses the target.
Porto are getting forward more after a tough opening few minutes. They're not making life easy for Thomas Tuchel's men.
Mount looks to play a through ball to Havertz, but Zaidu cuts it out. However, there was a foul on Mount after he released the ball and Chelsea have a free-kick.
Porto have Chelsea on the defensive as they continue to pepper their area with crosses.
A well-worked Porto corner leads to a chance for Pepe, which is blocked behind for another corner. Once again, there's a scramble at the near post. This time, Mendy has to prevent the corner kick itself from curling in and just about manages!
Chelsea look quite rattled, as did Juventus when Porto stunned them in the round of 16. The Blues look to get the ball in behind to Werner, but he is flagged offside.
GOAL, CHELSEA, MOUNT! 0-1: Mount receives the ball on the right from Jorginho, turns away from Zaidu and slots the ball calmly across the goalkeeper and into the bottom corner! Great goal!
Chelsea have their tails up now and seem to be in control of the game again. It's up to Porto to respond.
Mbemba looks to unlock the Chelsea defence with a long ball to Zaidu on the left, but the flag goes up for offside.
Azpilicueta gets a good block in off a FC Porto effort, turning it behind for a corner.
The ensuing corner is headed sweetly by Pepe, but Mendy makes a good save, tipping behind for another corner, which is less threatening.
HALF-TIME: PORTO 0-1 CHELSEA. It hasn't all been plain sailing for Chelsea, but Mount's stunning goal separates the sides at the break in Seville.
Nice build-up play from Porto, but Rudiger makes a good block off Uribe's effort.
The second half is underway in Seville. No changes over the break as far as we can tell.
Werner gets into a good position and rises to meet the ball in from the right, but just heads over the target!
Jesus Corona looks to beat Chilwell and goes down, but the decision does not go Porto's way there. It appeared only a half-hearted appeal.
Marega is slipped in behind Rudiger, but Mendy manages to save his shot at the near post. The Mali striker will be kicking himself!
Diaz looks to get in behind the defence, but Azpilicueta handles him well and takes the ball off him.
Corona looks to outfox James with some nice footwork, but the Chelsea man stands firm and takes the ball off him.
Porto cause problems for Chelsea off the ensuing corner as Pepe gets ahead of Mendy, but the flag goes up for offside against another Porto player.
Diaz goes for goal from the edge of the area with a wonderful shot, but just fires wide of the bottom corner.
Rudiger goes for goal from long range. Marchesin spills it and Werner pounces, sliding across the face goal for Havertz, but he is unable to finish off under pressure.
Mbemba picks up a yellow card for a poor challenge on Chilwell, seemingly born out of an attempt to clear the ball.
James' inswinging free-kick finds Azpilicueta, who heads wide at the near post!
Werner is off with Pulisic coming on. Giroud comes on in place of Havertz.
Marega has a go at goal on the half-turn, but fails to catch it cleanly, allowing Mendy to hold on.
The two teams are looking to hit each other on the break. There is still plenty of life in this tie.
Marega goes down under the challenge of Azpilicueta in the penalty area, but nothing is given. It was probably the correct decision not to award the spot-kick.
Porto head coach Conceicao picks up a yellow card, seemingly for interfering in play.
Rudiger does well to shield the ball from a frustrated Marega and win Chelsea a goal-kick.
Grujic picks up a yellow card for a professional foul.
Kante and Silva replace Mount and James as Thomas Tuchel looks to tighten up.