A familiar gaffe from Kepa Arrizabalaga led to Mane's four-minute brace shortly after the interval. It was the latest error in a vast catalog of ineptitude from Arrizabalaga, gifting the visitors a two-goal advantage.
Chelsea went down a man in the final moments of the opening half when Andreas Christensen hauled down Mane on the break. A VAR consultation overturned the initial yellow card against Christensen, ruling the Dane impeded a clear goal-scoring opportunity.
There was little separating the two sides in the opening half before Christensen being sent off swung momentum in Liverpool's favor.
Mane scored his first goal of the young campaign five minutes after the break when Roberto Firmino's brisk endline charge and ensuing cross found the Senegalese forward's noggin after his surging goal-bound run.
Kepa then doubled Chelsea's deficit moments later when the Spaniard's lethargic pass was punted directly into Mane's path just yards from goal, setting the fleet-footed poacher up for a facile finish to make it 2-0.
Chelsea were handed an opportunity to halve the lead when Thiago clipped Timo Werner in the penalty area with 15 minutes to play. Jorginho then missed his first penalty for the Blues in all competitions when Alisson lunged to deny him.
Jorginho had been successful on each of his previous eight attempts for Chelsea since misfiring on his final spot-kick for Napoli in November 2017.