Then-United manager Louis van Gaal was on the lookout for a winger and after Pedro left Barcelona for Chelsea, the Dutchman launched a bid for Mané, who was with Southampton at the time.
Van Gaal even had a chat with the 26-year-old forward about bringing him to Old Trafford.
However, Mané decided to stay at Southampton before heading to Liverpool for £34 million a year later.
Speaking in an interview with SuperSport, the Senegal international said:
I could not believe it, because even some club wanted me like Manchester [United].
The wrong team wanted me by the way - of course United.
I spoke with van Gaal and they even made an offer, but for me it was not the right club and not the right moment.
Mané has gone on to score 36 goals in 76 Liverpool appearances and has three in three so far this season.
Yet it could have all been different if Jürgen Klopp had managed to get his way - back during his days as Borussia Dortmund coach.
The current Liverpool boss wanted to sign Mané from Red Bull Salzburg in 2014, but with the teams unable to agree a fee, he would move to Southampton instead.
Yes, I met him, I spoke with him about it.
Salzburg were asking for €25 million, that was too expensive at that time, because I was playing in the Austrian league, no disrespect.
I was not that good for €25 million and that's why I didn't go there.