Chelsea are currently battling for a top-four spot in the Premier League, while they only won three of their six group matches to make the knockout stage of this season's Champions League.
Barcelona, on the other hand, are flying high at the top of La Liga, and breezed through their group unbeaten to make the round of 16.
Stay tuned for live minute-by-minute updates of the action.
CHELSEA: Courtois; Rudiger, Christensen, Azpilicueta; Moses, Kante, Fabregas, Alonso; Willian, Hazard, Pedro
BARCELONA: Ter Stegen; Roberto, Pique, Umtiti, Alba; Busquets, Rakitic, Iniesta, Paulinho; Messi, Suarez
The referee brings the second period to a close with Barcelona coming from behind to draw 1-1 with Chelsea in the first leg of their last-16 tie in the Champions League. Thanks for joining Sports Mole for our live coverage once again. Thanks for joining our live coverage of the match!
90 min+4 FULL-TIME: Chelsea 1-1 Barcelona
90 min+3 Not too much longer to play here, and Barcelona have a free kick in Chelsea's half of the field.
90 min+1 We are into the first of three additional minutes at the end of the match.
90 min BOOKING! Busquets (Barcelona) is booked for chopping Hazard to the deck.
89 min Suarez is not pleased with a challenge from Drinkwater, and it was very high to be fair. Alba also takes a tumble, but the left-back was not really touched. Stoppage in play at the moment.
87 min Vidal delivers high into the Chelsea box, but Courtois is on hand to make the claim.
86 min BOOKING! Morata (Chelsea) is booked for dissent.
86 min Chelsea send all three centre-backs into the Barcelona box for their latest free kick, but Willian's delivery is played short, and Barcelona crowd it out with Moses's final strike drifting wide.
84 min CHELSEA SUB! Drinkwater replaces Fabregas for the home side.
83 min CHELSEA SUB! Morata replaces Pedro for the home side.
82 min Chelsea break through Hazard, but Barcelona quickly have players back. Morata will soon join the action for the home side, and it would be some moment for the striker to pop up with a goal.
80 min BOOKING! Rudiger (Chelsea) is booked for a poor challenge on Roberto.
79 min Christensen is a touch fortunate as Suarez is adjudged to have felled the centre-back in a wide position. Chelsea need to be careful here as Barcelona push for a second goal in London.
77 min BOOKING! Suarez (Barcelona) is booked for dissent.
76 min Barcelona level the scores in the 75th minute as Iniesta jumps onto a loose ball before feeding Messi, who slides the ball into the bottom corner. Poor mistake from Chelsea, and Messi was never going to miss from that position. It is the Argentine's first ever goal against Chelsea!
75 min GOAL! Chelsea 1-1 Barcelona (Messi)
74 min Iniesta drives into the Chelsea box, but the midfielder's shot is blocked, and the home side can clear their lines. Willian, meanwhile, is back on the field following some treatment on his bloodied nose.
72 min Still no movement on either bench, but Dembele must be in the thinking of Barcelona boss Valverde. No sign of Morata or Giroud for Chelsea, meanwhile, which is not a surprise.
70 min Little over 20 minutes of football remaining, and Barcelona continue to dominate the ball.
68 min Alba delivers low into the Chelsea box, but Azpilicueta is on hand to make the clearance. It is all Barcelona as they continue to pass and probe in the final third of the field. Chelsea sit deep.
66 min Pass, pass, pass from Barcelona as they attempt to find a route back into this match. Still a lot of football to be played before the night is out, and the away side will continue to have the ball.
64 min BARCELONA SUB! Vidal replaces Paulinho for the away side.
63 min Chelsea take the lead in the 62nd minute as Willian again finds space on the edge of the box before finding the bottom corner with a brilliant effort! He deserves that after hitting both posts!
62 min GOAL! Chelsea 1-0 Barcelona (Willian)
62 min Fabregas strikes one from the edge of the Barcelona box, and his effort is deflected wide.
61 min Rakitic again delivers his corner straight into the arms of the waiting Courtois.
59 min... Rakitic delivers into the arms of Courtois.
59 min Super work from Suarez in a wide position as the striker wins a corner under pressure from Christensen and Moses. The resulting corner will be delivered into the Chelsea box...
58 min Little over 30 minutes of the first leg remaining, and we are still locked at 0-0. You do get the feeling that the opening goal is coming though as Barcelona continue to drive forward. We are entering the stage of the match where both managers will be considering changes.
56 min Pass, pass, pass from Barcelona as they continue to move from left to right. The Chelsea supporters are doing their best to raise their team, but they cannot get out at the moment.
54 min Suarez drills the ball across the Chelsea box, but the striker has no support.
54 min All Barcelona at the moment in terms of possession as they continue to boss the ball. That said, not too much to report in terms of clear chances. Chelsea are pretty comfortable at the moment.
52 min Hazard goes down inside the Barcelona box under a challenge from Umtiti, but the referee is not interested. That is not really Hazard's game - backing into the big centre-back! Morata, Giroud?
50 min Possession for Barcelona as they pass and probe in Chelsea's half of the field. Iniesta then has a go from outside the home side's box, but his effort was always moving wide of the post.
48 min Roberto drifts down the right before attempting to deliver into the Chelsea box, but the ball is behind for a goal kick. You do get the feeling that the home side need a goal in this first leg.
47 min... no changes from either side at the break, which is not too much of a surprise. However, I suspect that both managers will have alterations in mind as the second period develops in London.
46 min RESTART! Barcelona resume the action here...
The referee brings the first period to a close with the two teams level at 0-0, but it has been far from a boring stalemate. Indeed, Willian has hit both posts for Chelsea, while Hazard has also had a couple of really good chances. Barcelona have had plenty of the ball, but the Catalan outfit have been unable to really harm the hosts. All-action half of football from London!
45 min+1 HALF-TIME: Chelsea 0-0 Barcelona
45 min Messi drives into the Chelsea box before delivering low into Luis Suarez, but Rudiger is on hand to make the clearance. Barcelona are having a lot of the ball as we approach the break here.
45 min The Chelsea fans are up, and why not?! The home side have been excellent for the last 15 minutes or so, with Barcelona struggling to find their passing tempo in the final third of the field.
43 min CLOSE! Hazard misses the Barcelona crossbar with a volley after Barcelona had failed to clear their lines from a set piece. The away side really should be 1-0 behind in this game.
43 min Really good spell for Chelsea here as they continue to force the issue in the final third.
41 min POST! Willian now hits the other post with a super strike from outside the box!
40 min Fabregas attempts to slide a pass into Hazard, but the pass is just too strong, and Barcelona can build from the back. Little over five minutes of the first period remaining in the English capital.
38 min CHANCE! Pique heads wide of the Chelsea post after tangling with Rudiger inside the home side's box. Might have been a shout for a penalty there?! No real call though.
37 min Hazard is the danger man for Chelsea as the Belgian continues to find space down the left. Barcelona have not really created a chance since Paulinho headed wide of the post in the 15th minute.
35 min Really good spell for Chelsea as they continue to force the issue on the counter-attack here.
33 min POST! Willian rattles the post with an effort from the edge of the box following a super piece of work from Hazard. So unlucky from Willian; the strike was sensational.
33 min Iniesta cannot find Messi in the final third and Chelsea break once again through Hazard. The Belgian is slowed down in the final third, however, before Roberto goes through the back of him.
31 min... SAVE! Ter Stegen is across to keep out Alonso's free kick.
30 min BOOKING! Rakitic (Barcelona) is deservedly booked for fouling Willian just outside the Barcelona box, and Chelsea now have a free kick in a very dangerous position here...
30 min Barcelona continue to dominate the ball, while Chelsea are struggling to make it stick in the final third. We have not seen too much from Luis Suarez in the first 30 minutes of this match.
27 min Little over 15 minutes of the first period remaining, and we are still goalless. Barcelona have had a lot of the ball, but clear chances have been few and far between. Chelsea have not really been able to keep the ball in the final third as Morata and Giroud watch on from the bench here.
25 min Chelsea are fortunate as the ball just fails to fall for Messi following a super pass from Iniesta. Chelsea are riding their luck at the moment as the away side continue to dominate the ball.
23 min Rakitic delivers a dangerous cross into the Chelsea box, but Moses manages to clear ahead of Umtiti, who looked favourite to make contact. Barcelona are having lots and lots of the ball here.
21 min So, still goalless with 21 minutes on the clock, and Chelsea boss Conte will be pretty pleased with what he has seen thus far. Hazard struck over the Barcelona crossbar early on in Chelsea's best chance, while Paulinho headed the away team's best opportunity wide of the post from a Messi cross.
19 min Alonso has just bundled into the back of Messi. Had a few nibbles at the Argentine!
18 min Serious pressure from Barcelona at the moment as they pin Chelsea to the edge of their own box. Just a few signs that Messi is starting to dictate this game as he continues to get on the ball.
16 min CHANCE! Big chance for the away side as Messi finds the head of Paulinho with a super cross, but the Brazilian's effort is just wide of the post. Wonderful cross from Messi there.
15 min Pass, pass, pass from Barcelona as they build from a deep position here.
14 min Smart work from Hazard as the Belgian collects a super pass from Fabregas before delivering low into Pedro, but Iniesta is on hand to make the clearance before Kante handles outside the box.
12 min It is Barcelona back in charge of the possession as they pass and probe in Chelsea's half here.
10 min Moses delivers low into the Barcelona box, but Busquets manages to beat Willian to the ball. Rudiger then heads just wide of the away side's post from the corner. Really good spell for Chelsea as they keep the pressure on the visitors, who have been without the ball for the last few minutes.
8 min... Fabregas delivers into the Barcelona box, but Busquets is on hand to make the clearance.
7 min Fabregas is standing over a free kick outside the Barcelona box...
5 min SHOT! Hazard works some space outside the Barcelona box before looking to pick out the top corner, and the attacker's effort is not too far away. Some strike from Hazard!
4 min Messi delivers a cross into the Chelsea box, but Alonso is on hand to make the clearance at the far post. It has been all Barcelona in terms of possession in the opening four minutes here.
2 min... it must be said that there is a wonderful atmosphere inside the stadium tonight. You do get the feeling that Chelsea need to start well, and indeed win tonight, if they are to stand a chance of progressing through this tie. The first free kick goes Barcelona's way as Willian charges Alba.
0 min KICKOFF! Chelsea kick things off on home soil...