A majestic solo dribble shredded Chelsea's defence before Messi played in Dembele for the second and the Argentine maestro killed the tie off when he smashed a third through the legs of Courtois again in the second half.
Barcelona coach Luis Enrique said he believes Lionel Messi will sign a new contract with the Spanish champions despite reports the five times World Player of the Year is stalling over a new deal.
News of all that's transpired on and off the football field.
'They were better than us for some spells and we know what awaits us over there' Valverde pointed to his team's sensational exit from last year's competition to AS Roma after a 4-1 cushion from the first leg and said they would be taking nothing for granted in Tuesday's return game at Anfield.
Barcelona have one hand firmly on the La Liga title after winning 2-0 at Alaves on Tuesday, leaving them 12 points clear at the top of the table with four games to play.
It was Messi's 30th goal in 39 competitive games against Atletico
"I don't know how this affects my future," Valverde said.
La Liga leaders Barcelona beat Real Madrid 1-0 to all but knock their rivals out of the title race on Saturday, while second-placed Atletico Madrid stayed seven points behind the Catalans with a 2-0 win at Real Sociedad on Sunday.
News of all that's transpired on and off the football field
A round-up of Wednesday's action in the UEFA Champions League.
Barcelona are in the middle of an injury crisis as they head to Valencia for Saturday's La Liga game looking to keep up with pacemaking pair Atletico Madrid and Real Madrid. Without injured goalkeeper Jasper Cillessen and right back Sergi Roberto for the last two games, Barca will also be missing defenders Jordi Alba and Gerard Pique after both were hurt in Wednesday's 4-0 win over Manchester City in the Champions League. Pique sprained his right ankle while Alba injured his left hamstring and both are out until November.
Pedro hit a first-half hat-trick as Barcelona cruised into the last 16 of the King's Cup with a 8-1 second leg demolition of lower league Huesca at the Camp Nou on Tuesday.
Barcelona coach Ronald Koeman has defended centre-back Gerard Pique's right to make comments about referees favouring Real Madrid.
Barcelona rarely looked capable of repeating their heroic comeback in the last 16 against Paris St Germain.
A dominant yet wasteful Real ravaged their rivals in the first half while spurning a string of clear chances at the Santiago Bernabeu.
Luis Enrique is set to leave a mixed legacy when he departs Barcelona but the coach can go out on a high by lifting a third consecutive King's Cup when his side meet Alaves in Saturday's final in Madrid.
Pep Guardiola's formidable managerial skills will be put to the test again when his stuttering ManchesterCity side visit his former club Barcelona in a top-of-the-bill Champions League clash on Wednesday.
Barcelona coach Luis Enrique was pleased they got straight back into their stride with Tuesday's 2-1 friendly win over the Los Angeles Galaxy.
Griezmann goal earns Atletico first win of season
La Liga leaders Barcelona won a tight and tense 'Clasico' 1-0 at Real Madrid on Saturday, beating their great rivals at their Bernabeu home for the second time in four days and moving a staggering 12 points clear of them in the standings.
A mesmeric Lionel Messi helped Barcelona to come from behind and beat Sevilla 2-1 in a thrilling encounter on Sunday as the champions kept the pressure on La Liga leaders Real Madrid, who saw off Leganes 3-0 thanks to a double from Gareth Bale.
Cristian Tello hit a hat-trick as Barcelona came from behind to win 4-1 in their King's Cup quarter-final first leg at Levante on Wednesday and Lionel Messi celebrated his 400th appearance for the Catalan side.
The win increased Zinedine Zidane's side's advantage at the top of the standings to six points
Lionel Messi's late penalty saw bedraggled Barcelona scrape a 2-1 victory over Leganes on Sunday at a divided Nou Camp as the La Liga champions looked as if they had still not recovered from their harrowing midweek defeat to Paris St Germain.
News of all that's transpired on and off the football field
Barcelona's hopes of staging another sensational Champions League comeback fell flat against a hardened Juventus side who held the Catalans to a 0-0 draw at the Nou Camp on Wednesday to reach the semi-finals 3-0 on aggregate.
Real Madrid's faltering title defence continued as they were held to a thrilling 2-2 draw at Celta Vigo on Sunday which saw them fall 16 points behind runaway leaders Barcelona, who beat Levante 3-0 to stay nine points clear at the top of La Liga.
Real Madrid's Sergio Ramos scored in the 90th minute to hold FC Barcelona to a 1-1 draw at the Camp Nou on Saturday.
Chelsea's Marcos Alonso and Real Madrid's Nacho were notable absentees in defence, along with Atletico Madrid midfielder Koke.
Subdued atmosphere at the Nou Camp after the deadly attacks in the Catalan capital and the town of Cambrils.
La Liga leaders Barcelona hit two goals in the final three minutes to earn a 3-2 win at Rayo Vallecano
AS Roma pulled off one of the great Champions League comebacks by knocking Barcelona out with a remarkable 3-0 win in their quarter-final second leg on Tuesday, overcoming a 4-1 deficit from the first game to reach the last four on away goals.
Messi, who has struggled for form in recent weeks due to a niggling injury, looked on a mission to grab the winner and after twice coming close he completed his treble to put Barca ahead in the 85th minute, reacting quickly to a poor Sevilla clearance to dink the ball over goalkeeper Tomas Vaclik.
Real Madrid talisman Cristiano Ronaldo and Barcelona striker Luis Suarez took centre stage on Saturday in bailing their teams out with late strikes to silence their critics following slow starts to the season.
Images from football matches played across Europe.
Cristiano Ronaldo scored his 400th goal for Real Madrid as Zinedine Zidane's side closed in on a first La Liga title since 2012, easing to a 4-1 win over Sevilla on Sunday while Neymar hit a hat-trick for Barcelona, who thrashed Las Palmas 4-1.
Barcelona completed one of the most extraordinary comebacks in European football history to knock Paris St Germain out of the Champions League on Wednesday with a 6-1 victory that rewrote the record books.
Check out the top footballers of the weekend...
Lionel Messi scored a penalty for the third Champions League game in a row with the Spaniards maintaining their winning start to the group stage.
Villarreal went top with a 1-0 win over Atletico Madrid on Saturday after a toothless Real Madrid were held 0-0 at home to 10-man Malaga and Lionel Messi suffered a serious injury as Barcelona beat Las Palmas 2-1.