Situated across from Dean Martin Drive, cocooned in the $1.9bn Allegiant Stadium from the 40C heat and sirocco blowing across the Mojave Desert on which Las Vegas is built, Manchester United’s US tour closed with a record of one win and three defeats following this 3-2 reverse to Borussia Dortmund that was an unwanted comedy of errors.

The German side’s winner derived from a third defensive malady of United’s evening. Aaron Wan-Bissaka’s loose pass went to Marco Reus who, after a one-two with Julian Brandt, slid the ball across for Youssoufa Moukoko to beat André Onana.

Pre-season friendlies can be placed in the “phoney war” file but Erik ten Hag and his squad jetted out of Las Vegas immediately afterwards regretting, too, the defeats to Wrexham (3-1, with a junior team), and Real Madrid (2-0), following the 2-0 win over Arsenal in the tour opener.

Until Antony’s second half equaliser, Donyell Malen’s two goals had given Dortmund a first lead via 18 seconds – the gap between the strikes – of anti-professional play.

First though, Diogo Dalot decorated this contest with a 20-yard finish that sailed beyond Gregor Kobel into the top left-hand corner of the Dortmund goalkeeper’s goal, Donny van de Beek in assist mode with a touch to the Portuguese.

The XI Ten Hag sent out was not the finest he could field, as it had 11 changes and contained the lesser lights of Tom Heaton and Harry Maguire, plus Omari Forson, a 19-year-old attacker. The manager had followed the black eye he dealt Maguire by removing him as his captain with a rabbit punch of handing Scott McTominay the armband on the night – a decision that might euphemistically be described as more “tough love” from his manager.

These days Maguire exists in a quasi-perma state of low-confidence, a footballer who (unfairly) has become a pantomime villain for fans. There were a smattering of the jeers he can draw here, but they faded as, often, Maguire would look up and see Victor Lindelof drifting into the “John Stones” defensive midfield position from central defence, Brandon Williams moving into his area from left-back.

Lindelof was also spied in an attacking position to link play as Christian Eriksen, Jadon Sancho and Forson found space around him, but the latter’s outing ended after 37 minutes when Ten Hag replaced him with Antony. Almost certainly this was because of his clip, earlier, of Julian Ryerson: the left-back took umbrage at this and when Karim Adeyemi rushed over to protect his teammate Forson stuck his head into the No 27’s. Following this contretemps, each was booked and, on Forson’s removal, Ten Hag chatted for around 30 seconds with the youngster to explain the decision.

Omari Forson is spoken to by Erik ten Hag.

Omari Forson is spoken to by Erik ten Hag. Photograph: Matthew Ashton/AMA/Getty Images

United then crumbled as half-time neared, as Malen struck twice in a minute. His equaliser came when Adeyemi, despite being surrounded by a clutch of defenders, was able to force the ball to the No 21, who volleyed in. From the kick-off United descended further – possession was worked back but when Heaton tried to find to Lindelof, the pass was misplaced and Malen was set up once more.He did not miss.

Williams, who had played Malen onside, was unhappy, using invective to seemingly tell Heaton this was the keeper’s fault and not his. Maybe Ten Hag agreed because for the second half Onana replaced Heaton, and Williams remained on.

There was more to come from United calamity’s department, though. This time Maguire tapped to Eriksen in tight quarters, the Dane was dispossessed and Onana had to fling himself left to repel Sebastian Haller’s shot. Adeyemi missed the follow up but Maguire did not escape Onana’s ire – the Cameroonian sprinted over to give him a rollicking. Here was yet more evidence of Maguire’s loss of status.

What United needed was relief and Antony provided it. Van de Beek – inadvertently – contributed a second assist by making a block in Dortmund’s area and there was the Brazilian with his lethal left to score and ease his team’s mood.

Yet here was no new dawn of United solidity. Maguire, unluckily, deflected onto his own bar from Ramy Bensebaïni’s header at a corner, then the lively Adeyemi glided in but spooned wide.

Ten Hag sent for the calvary, removing every starter remaining apart from Sancho, as on came a band of A-listers – Jonny Evans apart – led by Bruno Fernandes, Lisandro Martínez and Marcus Rashford.

Another, Wan-Bissaka, was teed up by Rashford yet at close range he hoofed into the crowd in what was nearer to a NFL field goal attempt by the Las Vegas Raiders, who play here. After Moukoko’s winner he regretted this even more and toward the end Antony felt a similar emotion as, with his much less favoured right, he missed an easy chance from near-in.

Holding 61,100, the venue was not close to a sell-out for United’s first ever game in the neon-jungle that is America’s gambling capital. But on leaving Las Vegas, Ten Hag had a little to ponder.