Both competitive players at the very top of the professional game, the intensity of Premier League football can often cause disagreements and confrontation.
But now tasked with fighting for the very same cause - success under Erik ten Hag - some fans may be blissfully unaware of the past history that makes their Carrington embrace that tad bit sweeter.
If we cast our minds back to United's 1-1 draw with Chelsea at Stamford Bridge last season, our new signing Mason and Licha got into something of a heated spat.
After receiving the ball on the turn from David De Gea, Martinez cleverly flicked the ball past the former Chelsea man, before the two engaged in an aggressive battle for possession by the touchline.