Miguel Britos scored a dramatic 93rd-minute equaliser for Watford as Liverpool were held in a thrilling game at Vicarage Road.
The Reds, without Barcelona target Philippe Coutinho due to a back injury, fell behind to Stefano Okaka’s header.
Sadio Mane equalised with a clinical finish only for Abdoulaye Doucoure to restore the lead from close range.
Roberto Firmino’s penalty made it 2-2 before Mohamed Salah thought he had won it only for Britos to equalise.
In Jurgen Klopp’s 100th competitive game as Reds boss, Liverpool wasted a string of chances before Uruguay defender Britos headed over the line from close range.
Watford keeper Heurelho Gomes, who conceded the penalty after hauling down Salah, denied Alberto Moreno with a fingertip save.
Joel Matip also hit the bar and Dejan Lovren forced another good save from Gomes as the Reds dominated the closing stages until Watford’s late leveller.
Relive the action from Vicarage Road
New season, same old Liverpool
It was a case of new season but same old Liverpool on the opening day of the campaign.
As good as Liverpool were at going forward, their defensive frailties – which arose time and again last season – came back to haunt them.
Klopp’s side were behind after failing to defend the first corner of the match, unmarked Italian striker Okaka allowed to power home Jose Holebas’ delivery.
In the space of 161 first-half seconds, Liverpool went from outstanding at one end of the pitch to atrocious at the other.
They equalised with a sumptuous finish by Mane, the Senegal forward collecting a lovely flick by Emre Can before scoring from an angle.
It was Liverpool’s first serious attack of the game yet moments later they were trailing again after more awful defending.
The Reds’ defence made a hash of trying to clear Tom Cleverley’s low ball across the box and Doucoure slotted home from five yards – his second goal since joining Watford from Rennes in 2016.
A clumsy foul by Gomes on Salah allowed Firmino to make it 2-2 from the spot before the Brazilian turned provider with a delicious lob which enabled Salah, a £34m signing from Roma, to put his side ahead on his league debut.
It should have been the winner yet Liverpool’s defence failed to deal with another Holebas corner, allowing Britos to score three minutes into added time.