After missing out on his debut against LA Galaxy on Saturday, the Belgian striker struck in the first half to find the net for the first time since his £75 million from Everton last week.

It was the highlight of United's night after a game which also saw Juan Mata hobble off with an injury and Valencia receive a straight red card in the second half.

United had to come from behind at the Rio Tinto Stadium in Sandy, Utah, surrounded by the Wasatch and Oquirrh Mountain ranges, after Luis Silva had given the MLS side the lead.

Henrikh Mkhitaryan equalised with his second goal of the summer before Lukaku marked his second United game with a debut goal.

The game had briefly been in doubt as a hot day in Salt Lake City was interrupted by a thunderstorm close to kick-off. In the end the weather warning beamed into the stadium wasn't needed and United avoided another preseason cancellation.

After an experiment with a back three against LA Galaxy on Saturday night, Mourinho tried something more familiar against Real Salt Lake.

Victor Lindelof, the £31m summer signing from Benfica, started for the first time alongside Phil Jones in a back four that also included Timothy Fosu-Mensah and Daley Blind at full-back.

Lukaku started as the lone striker with support from Jesse Lingard on the left and Mkhitaryan on the right.

Real Salt Lake are a place below LA Galaxy, who lost 5-2 to United on Saturday night, in Major League Soccer's Western Conference.

But they beat Galaxy 6-2 earlier this month and they gave United a much stiffer test in the opening 20 minutes.

Marcus Rashford had already scored twice at the same stage against Galaxy but Real Salt Lake had the better of the opening stages here.

Former Manchester City winger Albert Rusnak caused problems for Blind down United's left, enough for Mourinho to get off his seat and into his technical area to bark instructions.

Lingard was forced into one last-ditch challenge under his own crossbar to stop Joao Plata from giving Real Salt Lake the lead.

They didn't have to wait long. After 23 minutes, Jefferson Savarino burst past Lingard and Blind to put Silva through. Silva still had work to do but brushed off Jones and poked his finish past Joel Pereira.

But the lead didn't last. Having barely threatened at all, Paul Pogba and Lingard combined on the edge of the box and Mkhitaryan fired his effort into the bottom corner.

Real Salt Lake have got more important games against Portland on Wednesday and Kansas on Sunday to think about and after 30 minutes made 11 changes. The first XI can be happy they gave United their first real test of the summer.

The second team couldn't live with the Premier League side quite as well and United were ahead before half-time.

After Mkhitaryan had played an inviting pass into Lukaku's path, the 24-year-old settled himself, took a touch around the goalkeeper and scored into an empty net.

Whatever the fixture, it is always nice to get the first one out of the way.

Just like at the StubHub Center two days ago, Mourinho made 11 changes at half-time. Mata only lasted 15 minutes before being replaced by Demetri Mitchell after taking a kick on the right ankle from Sebastian Saucedo.

It prompted a series of exchanges between Valencia and Saucedo before the United right-back went through the back of the Real Salt Lake player and was sent off by referee Allen Chapman.

It didn't do anything for Mourinho's mood, with the United manager already annoyed by Saucedo's challenge on Mata.

Still, it is now two wins out of two for United on their US tour before a date with Manchester City in Houston on Thursday.