Drag down or refresh for latest updates
Live updates
22:02 BST - FULL-TIME: It's all over in Madrid, where Atletico have resisted a Barcelona fightback to book their place in the last four. Barcelona had levelled the tie on aggregate within 25 minutes of tonight's start, but Lookman restored his side's advantage shortly after the half-hour mark. Aside from a goal ruled out by VAR, the Atletico Madrid defence stayed firm for the remaining hour to hold out for victory.
22:00 BST - FULL-TIME: There's the final whistle from the referee which brings down the curtain on Liverpool's Champions League campaign. The fought for the whole game, and looked so close at times to igniting the tie with a goal, but the PSG defence held firm and Dembele made his chances count. In the end, the French giants are the ones to book their place in the semi-finals.
21:55 BST - GOAL! Dembele has another after taking a slick pass from Barcola and that's the tie over.
21:41 BST - RED CARD! Barcelona are down to 10 men after Garcia brings down Sørloth to stop a clear goal-scoring opportunity. The visitors have it all to do in Madrid.
21:36 BST - GOAL! Oh dear, against the run of play, PSG have silenced Anfield. Dembele is the man to shoot from distance and beat the goalkeeper to make it 1-0 on the night and 3-0 on aggregate.
21:33 BST - CLOSE! Mac Allister now flashes a header across goal from a corner. This game has been absolutely enthralling.
21:32 BST - Barcelona mean business - Rashford and Lewandowski have come on in place of Torres and Lopez. Not bad depth to call upon!
21:31 BST - NO PENALTY! It's an unpopular decision at Anfield, but the referee overturns his decision due to a lack of contact in the challenge on Mac Allister.
21:30 BST - The referee has been invited to the monitor to take another look. We know what usually happens here.
21:28 BST - PENALTY! Liverpool have been awarded a penalty! VAR taking a look though...
21:22 BST - Liverpool, meanwhile, have started this second half incredibly well. Anfield is once again bouncing as they move the ball around and pile pressure on the PSG defence. Can they turn that pressure into goals?
21:19 BST - NO GOAL! Barcelona have the ball in the back of the net, but after a long look, it's ruled out by VAR for offside in the build-up.
21:08 BST - We are back underway in both games. Hopefully with more of the excitement we were treated to in the first halves in Liverpool and Madrid.
20:56 BST - Elsewhere, England Women have secured an impressive 1-0 victory over Spain in their World Cup qualifier at Wembley.
20:53 BST - HALF-TIME: There's the referee's whistle at Anfield where things remain goalless, which means PSG still lead 2-0 on aggregate. Liverpool and their fans threw everything at the Parisians in the early stages of that first half, and they will need more of the same in the second if they are to force a result here.
20:49 BST - HALF-TIME: We've reached the break in Madrid, where Barcelona lead 2-1 on the night and trail 3-2 on aggregate. It's been a great game so far, hopefully more of the same in the second half!
20:35 BST - CHANCE! Marquinhos has just shut down a big threat from Van Dijk who was about to pounce on a rebound and fire the ball in. Liverpool could have really lit the touchpaper of this tie if that had gone in. As it was, the defensive effort was immense.
20:33 BST - Oh no. Ekitiké has gone down with a serious looking injury and is pointing at his Achilles. He leaves the field and that unfortunately looks like the kind of injury that will end a season. Here's hoping it's not as bad as that. There was nobody around him, he got caught awkwardly in the turf by the looks of things.
20:31 BST - GOAL! Atletico hit back! It's a slick move as Llorente goes down the right then fires the ball across the defence, and Lookman slots it home. It's 3-2 to the Madrid side on aggregate.
20:24 BST - GOAL! Barcelona are level with Atletico Madrid on aggregate (2-2)! Torres gets a slick pass to break clear and sweep the ball past the flailing goalkeeper. There were not even 25 minutes on the clock when the hosts had their two-goal lead from the first leg decimated.
20:20 BST - CHANCE! Dembele has just flashed at one that he really should have buried into the back of the net. Instead the ball flies over the crossbar.
20:12 BST - There's no question that the two sides who lost in the first leg are throwing everything at their respective opponents in order to overturn those deficits. The atmosphere in Anfield is absolutely bouncing.
20:04 BST - GOAL! Barcelona have scored already! Yamal is the man to do it with barely four minutes on the clock, having taken advantage after Lenglet lost the ball. What have Atletico got here?
20:03 BST - After a moment of silence for the 97 who lost their lives in the Hillsborough disaster, we have kicked off in Liverpool.
20:02 BST - There's already been a save to be made in Madrid, with Yamal slicing through and trying to curl a shot into the left corner. Dangerous signs of the kind of mood they're in!
20:00 BST - And we are off in Madrid! Are there a couple of comebacks on the cards? Stay with us to find out...
19:45 BST - We are just 15 minutes away from our respective kick-offs in Liverpool and Madrid.
19:24 BST - In his programme notes, Liverpool captain Virgil van Dijk says despite the job at hand, this is the kind of occasion "we all live for".
"I couldn't be looking forward to tonight more, and I hope you guys feel the same," he wrote.
"Yes, we know the size and the scale of the task facing us, but these are the games, the nights that we all live for. If you can't get excited for this, then you're in the wrong sport, in my opinion.
"I said after the first leg in Paris that we will need something special if we are to progress to the semi-finals, and that applies first and foremost to our own performance, but also to the atmosphere and the support that you guys will provide. Both will need to be absolutely spot on if we are to have a chance.
"I have been very lucky to experience those nights where the connection between the fans and the performance has been unbelievable.
"I think of Manchester City, Roma, Barcelona of course, even Real Madrid both this season and last, and I can assure you all that everyone in this dressing room believes we can do something again this evening.
"Yes, the performance in Paris was not good enough, and we must improve in every area if we are to have a chance. Anfield, though, is different, and hopefully we can show that tonight."
19:17 BST - One thing is for certain, the atmosphere in Anfield will not disappoint this evening!
19:02 BST - Can Barcelona deliver a big performance this evening and seal a place in the semi-finals once again?
18:49 BST - The team news for tonight's Champions League clashes has arrived! Notably, Mo Salah has been dropped to the bench for Liverpool while Alexander Isak starts. PSG's Bradley Barcola has made the visitors' bench.
18:45 BST - "You never know with Liverpool". Are we in for another historic Champions League comeback under the lights at Anfield this evening?
18:15 BST - Will this affect tonight's visitors?
Earlier today, UEFA rejected Barcelona's complaint over the officiating in their first-leg defeat last week.
Barcelona appealed for a penalty after Atletico goalkeeper Juan Musso appeared to have put the ball back into play from a goal kick before defender Marc Pubill handled it inside the six-yard area to retake it.
Referee Istvan Kovacs waved play on, and the VAR team did not summon him to the monitor.
Barcelona launched an official complaint on Thursday, but UEFA's Control, Ethics and Disciplinary Body deemed the complaint to be inadmissible.
17:38 BST - Here are all the details for the four second-leg fixtures of the Champions League quarter-finals:
17:23 BST - Here's a reminder of how things unfolded in the first legs of these respective ties.
17:11 BST - Good evening and welcome along for our live updates from two huge second-leg ties in the quarter-finals of the Champions League. Liverpool host holders PSG at Anfield looking to overturn a 2-0 deficit from their loss in the first leg in Paris, while Barcelona head to the Spanish capital to take on Atletico Madrid with the exact same remit.
Stay with us as we bring you all the key updates from both games as they happen.