The forward’s brace helped Manchester United pick up all three Premier League points, with Edinson Cavani adding a late strike to conclude proceedings.
But it was Mason’s goals that helped to swing the game at Old Trafford, with the first coming from a free-flowing counter-attack within minutes of the second period kicking off.
Marcus Rashford started it off when he flew past Matthew Lowton on the left flank and then picked out Bruno Fernandes in the centre. The Portuguese midfielder had the presence of mind to dummy the ball and let it run through to Mason, who coolly slotted it past Bailey Peacock-Farrell.