Barcelona and Manchester United played out a thrilling 2-2 draw in the first leg of their Europa League play-off tie on Thursday, while Juventus were left frustrated by Nantes in a 1-1 stalemate.
The game at the Camp Nou brought together two European giants who met in two Champions League finals in 2009 and 2011, and who are both in excellent form domestically.
After a goalless first half, La Liga leaders Barcelona went ahead five minutes into the second half thanks to a Marcos Alonso header at a corner.
However, United drew level just three minutes later when Marcus Rashford beat Barcelona goalkeeper Marc-Andre ter Stegen at his near post to score a 13th goal in 15 games since the World Cup.
The Premier League side then took the lead just before the hour mark through a Jules Kounde own goal, but a Raphinha cross flew in inside the final quarter of an hour to secure a draw for Barca before a crowd of more than 90,000.
"I think it was a great game. Two attacking teams, I think it was a Champions League game, even more than that," United boss Erik ten Hag told broadcaster BT Sport. "We have to finish it in Old Trafford."
Barcelona coach Xavi Hernandez was left complaining that his side should have had a penalty for a handball by Fred.
"It's a stolen penalty," said Xavi. "I don't know why they don't whistle for penalties for handball now. It seems incredible to me. Incredible."
Winning the Europa League may represent the best chance for Juventus to return to the Champions League next season after they were handed a 15-point deduction in Serie A.
That punishment, for what the Italian Football Federation ruled was illicit transfer activity designed to artificially boost their accounts, has left the Turin giants 12 points adrift of the top four at home.
Against Nantes they looked on course for a comfortable win when Federico Chiesa nodded a ball across the face of goal for Dusan Vlahovic to open the scoring early on.
But French Cup holders Nantes equalised on the breakaway on the hour when Ludovic Blas ran through to finish emphatically.
A Chiesa shot then hit the underside of the bar and bounced down without quite all of the ball crossing the line, before it struck the post and rebounded away.
Nantes also survived a VAR penalty check for a handball deep in injury time, the referee instead giving them a free-kick and leaving Juventus with work to do in the return.
- Sevilla win, Roma lose -
Elsewhere, Monaco came from behind to triumph 3-2 away against Xabi Alonso's Bayer Leverkusen, with Axel Disasi scoring the winner in the 92nd minute.
An own goal by Leverkusen goalkeeper Lukas Hradecky had put Monaco ahead early on only for second-half goals by Moussa Diaby and Florian Wirtz to turn the game around.
However, Krepin Diatta pulled the principality team back level before France defender Disasi's strike.
Shakhtar Donetsk were 2-1 winners against Rennes as the Ukrainian club played their first European game since selling star winger Mykhailo Mudryk to Chelsea.
Playing in the Polish capital Warsaw, Dmytro Kryskiv put Shakhtar ahead and Artem Bondarenko netted a penalty before Karl Toko-Ekambi pulled one back for Rennes.
Jose Mourinho's Roma went down 1-0 away to Austrian champions Red Bull Salzburg with Argentine midfielder Nicolas Capaldo scoring a late winner.
Sevilla, the competition's most successful club, beat PSV Eindhoven 3-0 in Spain as Youssef En-Nesyri, Lucas Ocampos and Nemanja Gudelj all netted.
Ajax drew 0-0 with Union Berlin, while Sebastian Coates scored deep into stoppage time to earn Sporting a 1-1 draw with Midtjylland of Denmark in Lisbon.
The second legs will be played next Thursday with places in the last 16 up for grabs alongside the eight teams who topped their groups.
Fiorentina were the biggest winners in the first legs of the Europa Conference League play-offs as they trounced Braga 4-0 in Portugal.
Ciro Immobile gave Lazio a 1-0 victory against CFR Cluj while there were also first-leg wins for Qarabag, Trabzonspor, AEK Larnaca, Partizan Belgrade and Ludogorets.