The mental edge José Mourinho praised in the build-up was evident in a Manchester United victory which must surely be the template for the season. Fast, cold-eyed and a concerted unit: these were the key components in their defeat of Young Boys on an artificial pitch flagged up as awkward but which proved a slick surface for United to show their class.

Mourinho pointed to his side’s ruthlessness. “At half-time I told the players this the third time in a row we arrive at half-time winning 2-0. Against Burnley we didn’t finish off but we didn’t concede, against Watford we conceded and were in trouble [winning 2-1]. Today we could have had more of that but our best period was when we scored in the second-half and killed the game.

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“The players were ambitious and tried to score the third goal to kill the game. But after two defeats [now] three matches away, three victories – I don’t say phenomenal performances, solid performances and let’s go back home.”

Of the playing surface, Mourinho added: “I don’t understand how you can play the best European competition on artificial surfaces.”

He had made five changes from the Watford game. There was a rare rest for Alexis Sánchez – he was a substitute – and a debut for Diogo Dalot, the young summer signing from Porto having recovered from a knee injury. Luke Shaw, Fred, Anthony Martial and Marcus Rashford were the other additions as United set out against an opposition recently crowned Swiss champions for a first time in 32 years. Gerardo Seoane sent his team out in the 4-4-2 that had won their opening six league games in a unbeaten start of 10 games.

Facebook Twitter Pinterest Anthony Martial scores their third goal on his return to the starting lineup. Photograph: Matthew Childs/Reuters

Mourinho talked Dalot up beforehand by pointing to how he played for Porto against Liverpool at Anfield last year, and the defender made an eye-catching start to his United career, being alert in defence and eager to rove forward. “I am happy,” Dalot said. “My team-mates helped me so much, I think I played good.”

His manager said: “He is a 19-year-old player who has more than 10 years to play for Manchester United.”

United headed into the interval with a priceless 2-0 lead as Shaw, Martial, Fred and Pogba all combined before some Fred Astaire-like footwork from the latter ended in David von Ballmoos being beaten by a slick left-foot finish.

This left Mourinho motionless but he was a picture of delight when Pogba coolly doubled the lead from the spot. The referee awarded the penalty after he adjudged Shaw’s cross to have been handled by Kevin Mbabu.

It looked harsh but United hardly cared. This had been their most clinical display this campaign and Mourinho’s half-time order to the players was, as he confirmed, to make sure they kept on keeping on.

Martial soon suggested they would by spinning his man with ease and racing at a flat-footed defence that only just managed to recover. The attacker was again the player to trouble Young Boys when, this time moving along the right, he found Rashford but the No 10’s intended pass to Lukaku lost the ball.

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Moments before, Lukaku might have scored when slipped in by Rashford but he fluffed the chance, yet it was clear how dominant the visitors had become. At this juncture the only danger was complacency and there was a wake-up call when Roger Assalé was fed in the area and for a moment looked to have pulled a goal back.

Yet the kind of evening this was for United was summed up by Martial –who has been at loggerheads with the manager – registering the third from a clever pass from the outstanding Pogba. This came on 66 minutes and a little later Mourinho decided Fred and Rashford could be protected as he replaced them with Juan Mata and Marouane Fellaini.

Martial’s goal was his first since 20 January at Burnley and given that Mourinho had lost his previous two matches in Switzerland, there was further succour to be had.