The Senegal international was the busier of the two goalkeepers in the opening 45 minutes and he produced one very smart stop to deny a header from Pepe.
After the break, Mendy produced a hugely important save from Moussa Marega after Antonio Rudiger had switched off. Has blossomed into a hugely reliable figure between the posts. 8
The club captain’s lack of composure on the ball was evident throughout as Porto pressed Chelsea high up the pitch. His defensive instincts, however, remain better than most.
There was a moment of danger in the second period when Luis Diaz was slipped behind the Blues backline only for Azpilicueta to spot and track the run and ensure there was no shooting opportunity.
The 31-year-old should have got on the scoresheet just after the hour mark, though. He somehow headed a Reece James free-kick wide from six yards out. 7
The Dane was preferred in the centre of the defence ahead of the experienced Thiago Silva by Tuchel but looked a little nervy in the opening 30 minutes as he twice overhit routine long passes forward.
Christensen improved as the game progressed and it was a sign that when Silva was introduced with ten minutes to play, he was moved onto the right of the back three instead of being brought off. 7
The German defender started just days after getting involved in a training ground scrap with Kepa Arrizabalga. For the most part, Rudiger was a solid presence on the left of the back three.
He did though lose Marega in the second period and the Porto forward was only denied by a good stop by Mendy. 7
Chelsea didn’t make the most of the space afforded to James in the opening period. He was able to break down the right flank unchallenged on multiple occasions only for the ball to not be delivered or a pass to be wasted.
James’ defensive abilities were tested more in the second half as Porto attempted a fightback and he stood up well against the threat of Diaz. Was brought off with eleven minutes to play. 7
Struggled in the opening 30 minutes to help contain Porto, who were in control of the game at that point. Yet made a telling contribution to turn the tie in Chelsea’s favour as it was his pass into Mason Mount that led to the Blues’ opening goal.
Jorginho improved in the second period and kept things tidy in possession, although his defensive weaknesses were exposed on a couple of occasions. 7
The Croatian was poor against West Bromwich Albion on Saturday but was much better in Seville. There is still a lack of awareness to Kovacic’s game without the ball, but there’s no denying his talent with it.
It was his pass, although admittedly it was initially intercepted, that led to Chilwell’s late goal. 7
Brought back in at left wing-back ahead of Marcos Alonso, Chilwell wasn’t as adventurous in the opening period as James on the opposite flank but was solid defensively.
It was much the same story in the story in the second half but, with five minutes to go, Chilwell collected a loose ball in the Porto defensive third and advanced on goal. He rounded Agustin Marchesin and tucked the ball home to put Chelsea in control of the tie. 8
What is left to say about the academy graduate? This wasn’t Mount’s most complete game in a Chelsea shirt but he stepped up and delivered when needed.
On the half-hour mark, Jorginho slipped the ball into the feet of the England international who in one motion, turned and brought the ball under control. He then fired a shot into the bottom corner to put the Blues ahead.
Mount wasn’t as involved in the second period but his usual energy and desire to press opponents remained before he was brought off for N’Golo Kante as Tuchell looked to see the game out. 9
The German started ahead of both Olivier Giroud and Tammy Abraham but struggled to have a meaningful impact on the game. There were a couple of neat touches from the German early on but he faded as the match progressed.
Havertz did seemingly have a glorious chance to add to Chelsea’s lead in the second period when Timo Werner squared the ball back to him from close range. Havertz missed the chance but was spared as the offside flag was raised. 6
There was plenty of space behind the Porto defence for Werner to exploit in the first half, but due to poor passing from his team-mates the German was left frustrated. He touched the ball on only nine occasions in the first half.
A header early into the second period that went over the bar was Werner’s best sight of goal. He worked hard before being brought off in the 65th minute but Chelsea need more from the German in the final third. 6