Manchester United needed a 76th-minute goal from defender Raphael Varane to eke out a 1-0 win over Wolverhampton after being outplayed for long periods of their Premier League opener on Monday.
The former France center back headed home from point-blank range after Aaron Wan Bissaka ran onto a lofted pass from Bruno Fernandes and lobbed a cross into the six-yard box.
It was a rare slick move from United, which gave competitive debuts to goalkeeper Andre Onana and Mason Mount and failed to look cohesive against a visiting team that dominated midfield and was a constant danger on the break.
Wolves struck the post through Matheus Cunha early in the second half, while substitute Fabio Silva drew two saves from the feet of Onana in the closing stages as United hung on at Old Trafford.
Mount, who joined from Chelsea, lasted 68 minutes before being substituted after an ineffective display in a midfield three with Fernandes and Casemiro that looked disjointed.
Onana had a much more impressive debut, making six saves in total, though had a worrying moment deep into stoppage time when he appeared to clatter into Wolves substitute Sasa Kalajdzic in an aerial collision.
The incident was reviewed by video but no penalty was given, much to the annoyance of Wolves manager Gary O’Neil, who was shown a yellow card in the technical area to mark his first match in charge after being hired last week.