Marouane Fellaini’s first league goal of the season, a thundering strike from Jesse Lingard and an injury-time Antonio Valencia finish secured maximum points for Jose Mourinho’s side and lifted into fifth place in the table, piling the misery on Boro at the end of a week in which Aitor Karanka lost his job.
Mourinho – whose men are now unbeaten in 18 top-flight matches – had claimed that a draw would be a good result for his side, given their exhaustive exploits in the FA Cup and Europa League this week, and Boro certainly started in the ascendancy against a United side shorn of a number of first-team regulars.
But Fellaini’s 30th-minute header gave the visitors a stranglehold that they never looked likely to relinquish and Lingard’s emphatic strike in the second half left the home side on course for a 14th defeat in 28 league games this season.
Rudy Gestede got a goal back in the closing stages – Boro’s first in 509 minutes of league action – but Valencia pounced on a horror moment for ex-United goalkeeper Victor Valdes to ensure United move to within three points of the Champions League places, having played a game fewer than fourth-placed Liverpool, who face Manchester City later on Sunday.
The pressure is growing on second-bottom Boro, however, with five points now separating them from safety, though they do have a game in hand on Hull City and Swansea City above them.