Mount, 27, came through the full 90 minutes at the Stadium of Light — his first league start of 2026 — having been sidelined by injuries that have restricted him to 23 appearances and limited his influence on what has otherwise been one of United's strongest runs of form in years under Michael Carrick.
Owen, appearing on Sky Sports' coverage, questioned both the quality of the performance and the player's suitability for the role United paid for when they spent £55 million bringing him from Chelsea in 2023.
"Mason Mount is working hard, but right now he's not performing anywhere near the level Manchester United expected when they signed him. He looks a little slow in possession, a bit laggy in transitions, and he's not really influencing the game enough in midfield. At the moment, Sunderland look more energetic and sharper in midfield areas. Manchester United need more intensity and personality from Mount because games like this demand it."
Tony Mount responded on Instagram with a pointed rebuke.
"Maybe not starting a game for five months has something to do with looking rusty. Owen, you fool."
Mason Mount has spoken to the BBC about his own view of the season and his belief in what he can still contribute.
"I will always back myself. I know what I'm about and what I can bring. I love being a part of a massive club. It's my third season and it's flown. I'm a bit older now and I've got a bit more experience. There are going to be a lot more games next season. Being a part of getting this club back to the top, where it deserves to be, is super special."
Mount's injury record at United has been a persistent issue. Since arriving from Chelsea he has sustained multiple separate muscle problems, limiting him to 70 appearances across three seasons. He has scored four goals this term but has been absent between December and his return at Sunderland.
He is out of contract in 2028 and has been linked with a summer exit, though his determination to prove himself under Carrick suggests he would prefer to fight for his place.