Arsene Wenger was left to rue the gamble of dropping leading scorer Alexis Sanchez as Arsenal lost to Liverpool at Anfield and surrendered their top-four place as a result.
By the time the Frenchman corrected his mistake for the start of the second half the hosts were already ahead through goals from Roberto Firmino and Sadio Mane.
Sanchez then compounded the scrutiny on his manager by providing the assist for Danny Welbeck's goal, which changed the complexion of the game but not the result as Georginio Wijnaldum wrapped things up in added time.
Liverpool's 3-1 win lifted them into third place, with the Gunners dropping to fifth only one point above Manchester United.
It was only the Reds' second league win of 2017, the other coming at home to Tottenham, but extended Jurgen Klopp's record against his top-six rivals to 19 points from nine games this season.
By contrast Wenger has won just three times in their last 24 away games at Anfield, Chelsea, Tottenham, Manchester City and Manchester United and this performance gave him more questions to answer after an insipid first half played directly into Liverpool's hands.
Wenger's decision to drop 20-goal Sanchez in favour of Olivier Giroud because he wanted to be more direct and strong in the air appeared to have an immediate - and detrimental - effect on his side.
Liverpool had been torn apart by Jamie Vardy's pace running in behind in their loss to Leicester on Monday night, but without that threat from the Gunners Klopp's side were more than comfortable.
Scroll through the gallery at the top of the page to see the full Liverpool vs Arsenal player ratings…
Additional reporting by PA.Reuse content