Liverpool defender Virgil van Dijk's embarrassing mistake left the defender red faced at St Mary's, despite the Reds easing to a 2-0 over Southampton.
The £75m defender moved to Anfield on New Year's Day, with the Dutchman returning to face his old side for the first time on Sunday.
Footage taken before the game shows Van Dijk exchanging pleasantries in the tunnel area, before attempting to enter the home dressing room. Realising his mistake, the Dutchman attempted to casually stride off without much fuss, but unfortunately for the Reds ace, it was all caught on camera.
The 26-year old would end up having the last laugh though, putting in a solid performance as goals from Roberto Firmino and Mohamed Salah wrapped up a comfortable victory for the Reds.
Van Dijk endured a hostile reception from home supporters throughout the game, but his performance led boss Jurgen Klopp to heap praise upon him.
"He did really well and dealt with the situation fantastically," Klopp told Sky Sports. "We had a little talk before the game, asking him what he thought - 'No, I'm fine, boss'.
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"I didn't want to make him nervous if he isn't, obviously he wasn't. The crowd is there to make life difficult for the opponent, but it wasn't too difficult for him from this point of view and I'm happy about that."