But it was Will Keane who grabbed the first goal of the game, being teed-up by Juan Mata and aided by a howler from Latics keeper Jussi Jaaskelainen.
And United continued to dominate in the second half, with Mata – whose future under Mourinho, the man who sold him at Chelsea, thought to be in doubt – pulling the strings.
Mourinho’s men doubled their lead through Andreas Pereira, who rifled a shot into the top left-hand corner from inside the area.
And Wigan’s main signing of the summer – the former Manchester United man Nick Powell – made his second debut for his new club after 68 minutes.
Varela and Blackett came on for Daley Blind and Herrera as Mourinho took a look at some of his squad players.