Not in a million years was it a red card challenge - Refs saw it again afterwards in replays and they have said it was a yellow , its a yellow card challenge.
Serious foul play
Spitting at an opponent or any other person
Denying the opposing team a goal or an obvious goalscoring opportunity by deliberately handling the ball (this does not apply to a goalkeeper within their own penalty area)
Deliberate fouls that deny an obvious goalscoring opportunity to an opponent moving towards the player's goal (D.O.G.S.O.)
Using offensive, insulting or abusive language and/or gestures
Receiving a second caution in the same match:39
Thats what gets a red card and the Maguire challnge on Mane falls into none of them
It falls under a) Serious foul play and/or b) DOGSO. Mane has a goalscoring opportunity if there's no foul. It wasn't a mistimed challenge, the opponent knew exactly what he was doing, and hoped he would get away with it. Which without VAR, he did. About 5 minutes later, he scored.
The ref with the host broadcaster insisted the Keita call wasn't a penalty, despite what the replays clearly showed. Even the match commentators questioned his judgement. A replica of the same foul came in the England-Italy friendly last year, discussed in this thread from Post 66, where a penalty was then given by VAR.
Since then, the same ref who got two major decisions wrong in our game has given a ghost goal to our rivals for a clear handball. Every week it's the same names in the spotlight, making wrong decisions which affect results. They need VAR, we need VAR, so we can get up to the 99.3% correct decision rate VAR provides.