The South American scored Liverpool’s goal of the season at St Mary’s last term after a brilliant long-range strike against Ronald Koeman’s side.
Coutinho emulated his effort on Sunday as the former Inter Milan midfielder picked up the ball and beat two players before he guided a low finish past Fraser Forster from outside Southampton’s area.
Daniel Sturridge doubled Liverpool’s advantage before Simon Mignolet saved Sadio Mane’s penalty in the second half.
However, the Saints completed a memorable comeback after Sadio Mane and Graziano Pelle levelled the game at 2-2 before the Senegal international netted a winner four minutes from time.
Moreno, who wasn’t part of Jurgen Klopp’s match-day squad, sent a message to Coutinho via his Instagram account.
Moreno wrote: “Come on guys💪🏻💪🏻🔴🔴”
Coutinho scored Liverpool’s goal in a 1-1 draw with Manchester United in the second leg of their Europa League last-16 clash on Thursday night.
The Brazilian moved to Liverpool in an £8m deal from Inter Milan in January 2013 under former manager Brendan Rodgers.
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