On the night Queen Elizabeth II was announced dead, Spanish side Real Sociedad narrowly defeated Manchester United 1-0 in one of the opening games of the UEFA Europa League.
The usual chants in support of United and against the club's owners the Glazer family were heard once the game started, but the atmosphere felt more subdued than usual.
Erik Ten Hag described Brazil forward Antony as United's "missing link" after Brazil forward scored on his debut against Arsenal on Sunday following his £82 million move from Ajax.
But the 22-year-old struggled to make an impact during a disjointed United performance.
Cristiano Ronaldo was making only his second United start this season, while Brazil midfielder Casemiro was given his first start since arriving from Real Madrid.
Neither player could spark United, who saw a 35th-minute header from Ronaldo correctly disallowed for offside.
Sociedad clinched their victory in the 59th minute when United defender Lisandro Martinez was controversially penalised for handball.
The ball only hit Martinez's arm after bouncing off his knee but following a VAR check the decision was confirmed and Brais Mendez stroked the spot-kick past David De Gea.
After winning four successive Premier League games, United were beaten for the third time in boss ten Hag's reign.