Martial and Rangnick came to blows after United’s disappointing 2-2 draw away at Aston Villa when the former Leipzig boss accused the French forward of refusing to play in the game at Villa Park.
United cruised to a 2-0 lead following a Bruno Fernandes brace, but a Coutinho-inspired performance saw the Brazilian score and register an assist to leave United fans reeling at more dropped points.
Rangnick brought on Jadon Sancho, Jesse Lingard and Donny van de Beek in an attempt to regain the lead, but there was a severe lack of a striking option.
Martial would have provided attacking nous for the Red Devils, but his absence was criticised by Rangnick, who accused him of purposely refusing to play.
Yet the German claimed their issues had been resolved when he faced the press ahead of the away clash at Brentford on Wednesday.