Manchester - Manchester United landed another body blow to Manchester City's hopes of retaining the Premier League title with a 2-1 derby win at the Etihad that leaves the champions 14 points adrift of runaway leaders Liverpool.
United remain eight points adrift of their neighbours, but move up to fifth and within five points of fourth-placed Chelsea to haul themselves back into contention for a return to the Champions League next season.
Referee Anthony Taylor amazingly did not point to the spot in the first instance, but was quickly corrected by a VAR review.
Firstly, Rashford curled an effort wide with just Ederson to beat form a fine pass by Martial before he fired another effort off the bar.
The home side were also furious when Fred was not penalised for handball as he blocked Kyle Walker's cross inside his own area with VAR this time backing Taylor's decision not to give a spot-kick.
Otamendi gave City life five minutes from time when he rose highest to meet Riyad Mahrez's corner.
The Norwegian was facing questions over his future just six days ago after a 2-2 draw with Aston Villa left United with just four wins from their opening 14 league games.