Rob Green
Former England goalkeeper on BBC Radio 5 Live

Porto are trying something different with bringing Mehdi Taremi on. His chance was one of the few times Porto have been able to get behind the Chelsea defence and there were three players queuing up on the penalty spot to head it.

It wasn't enough to test Edouard Mendy but it's the first shot they have had in the game... and as a Chelsea fan, you'll take that.

PSG are playing like a team that are 4-0 up, not fighting for their Champions League future. All the tricks and flicks are coming out of the bag, first from Angel di Maria, and then from Neymar again.

It's great to watch, but must be making Mauricio Pochettino a bit nervous on the touchline. But PSG keep hold of the ball this time, although the move ends with a low cross from the left going into the hands of Bayern keeper Manuel Neuer.

This is probably the first time Porto have got in behind Chelsea through their own creation.

It's flicked into Jesus Corona in the box. He lifts it back into the middle for Mehdi Taremi but he can't generate enough pace on his header, which bounces near the bottom corner for Edouard Mendy to gather in.

Leroy Sane, up against the new defender Mitchel Bakker, could have a key role in this match for Bayern.

He slides a low pass in to the feet of Thomas Muller, but Keylor Navas is close enough to get his body in the way, the shot hits him and it's over the top. Good save.

Rich: Interesting stage of both ties. One goal for PSG or CFC and it is game over. Who is brave enough!

Decent one-touch passing from Porto down the left but the cross doesn't match in quality.

Marko Grujic then brings down Christian Pulisic. That's his last action too as he's replaced by striker Mehdi Taremi for Porto

A reminder of the task for Porto... They need two goals to take this to extra-time.

Chelsea have only conceded two goals in the entire competition so far this season. They have trailed for only four minutes too - in their final group-stage game against FC Krasnodar.

PSG defender Abdou Diallo looks like he's pinged a hamstring. Keylor Navas chucks the ball out and that's game over for the 24-year-old Senegal left-back, with 20-year-old Mitchel Bakker, a Netherlands Under-21 international, thrown into the action.

Rob Green
Former England goalkeeper on BBC Radio 5 Live

Porto are spent now, they're knackered.

We were wondering how long they could keep this high press up for and 56 minutes is your answer!

Chelsea win the ball in Porto's half. N'Golo Kante breaks away, plays in Mason Mount and he sets himself to smash it across goal but Wilson Manafa comes across to make a potentially goal-saving block. Brilliant defending!

Brilliant skill from Angel di Maria and he fires a low cross across the face of goal but Neymar agonisingly can't get a touch. Any touch and it's in the net.

Think Gascoigne in the 96 Euros semi-final against Germany. Or ask your parents.

A pull-back on the shirt of Neymar and David Alaba gets a yellow.

Mason Mount threads it through to Ben Chilwell on the left. He cuts it back into the middle and finds Christian Pulisic.

It comes at Pulisic with pace and he can't sort his feet out, instead slicing it wide of the right post. What a chance!

Zaidu's swinging cross from the left is seen off by Reece James. Porto are starting to push more players forward...

Edouard Mendy catches another cross.

Di Maria slides a pass through the Bayern defence and it's one for Kylian Mbappe to chase after, but away goalkeeper Manuel Neuer has a superb starting position and makes a sliding challenge outside the area that his back four would be proud of.

A chance for Bayern early in the second half. Eric Maxim Choupo-Moting can't get a clear header on Leroy Sane's pass and it falls to David Alaba.

However, the Austria full-back, making his 425th appearance in all competitions for Bayern but set to leave on a free transfer in the summer, can only pull it wide from 20 yards out.

Otavio eventually swings a dangerous cross in towards the backpost but Reece James is there to nod it away.

Edouard Mendy comes to collect the resulting set-piece and gets fouled.

It's much the same as the first half at the moment. Porto are moving it from side-to-side but not getting in behind the Chelsea backline.

Time for the second half in Paris. This one's very much in the balance. Who's going into the semi-finals to play either Manchester City or Borussia Dortmund?

Nice run from Christian Pulisic. He weaves past Sergio Oliveira and gets caught late. Straight into the book.