Salah appeared offside Trent Alexander-Arnold passed the ball forward to him.
The Egyptian crossed the ball from the right-hand side with no Liverpool player able to get on the end of it.
After Andrew Robertson had put another ball into the box, Salah again picked it up before putting a delivery in.
It was from this one that Naby Keita netted his first Liverpool goal.
And despite Salah having been offside in the buildup, Sky Sports presenter Kelly Cates flagged up the VAR quirk that would have meant the goal still stood.
She said: “There is an offside in the buildup to this goal but the VAR centre have told us that when VAR is introduced next season this isn’t a goal that would be disallowed because the Southampton defence has a couple of opportunities to reset.”
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