Sadio Mane scored his first goal for Liverpool as they won 4-0 against a Barcelona side containing Luis Suarez and Lionel Messi in the International Champions Cup at Wembley.
Mane, a £34m summer signing, opened the scoring on 15 minutes before Javier Mascherano scored an own goal.
Divock Origi and Marko Grujic were also on the scoresheet in the second half.
England striker Daniel Sturridge missed the game with a hip injury, while James Milner limped off before half-time.
Liverpool manager Jurgen Klopp said Milner had injured his heel. "It is not too good," said Klopp. "He will have a scan and then we will know more."
The Reds begin their Premier League campaign at Arsenal on 14 August.
The game drew the second largest attendance at Wembley, with a crowd of 89,945 turning up to watch.
Spain striker Fernando Llorente made his debut for Swansea as they beat Ligue 1 side Stade Rennais 1-0 at the Liberty Stadium thanks to Jay Fulton's second-half header.
A sixth-minute penalty from Leonardo Baptistao gave Espanyol, now managed by former Watford boss Quique Sanchez Flores, a 1-0 win at Everton.
Midfielder Idrissa Gueye made his debut for the Toffees.
Crystal Palace beat Valencia 3-1 at Selhurst Park, Hull lost 2-1 to Torino in Salzburg, while Watford squandered a 2-0 lead to draw 2-2 with Lorient at Vicarage Road after Troy Deeney and Odion Ighalo had scored for the Hornets.
Both Stoke and West Brom suffered 1-0 defeats, to Hamburg and Mallorca respectively, while Middlesbrough drew 0-0 with Real Sociedad.