The Reds were crowned as Premier League champions last week after Chelsea’s victory over City at Stamford Bridge.
And Jurgen Klopp’s side were hoping to continue their excellent form at the Etihad Stadium, but suffered only their second defeat of the season as Pep Guardiola’s men laid down a marker.
Goals from Kevin De Bruyne, Raheem Sterling, Phil Foden and an own goal from Alex Oxlade-Chamberlain sealed a comfortable win for City.
After the game, some Arsenal fans made the tongue-in-cheek point that their Invincibles side of 2003/04 managed to continue the rest of the campaign unbeaten after sealing the title.
And some supporters also claimed that Liverpool’s 2019/20 side had some way to go before being compared to teams such as Manchester United’s 1999 treble winning season.
Arsenal’s feat of completing an entire season unbeaten remains unmatched in the Premier League era.
Arsene Wenger’s side went on to stay undefeated until the following season when Manchester United ended their run at 49 games.