Lisandro Martínez believes André Onana’s disagreement with Harry Maguire in Manchester United’s 3-2 defeat by Borussia Dortmund on Sunday was required to ensure the defender remained focused.

The incident occurred in the second half of United’s final tour match at Las Vegas’s Allegiant Stadium when Maguire passed to Christian Eriksen who was dispossessed and Onana had to save from Sébastien Haller.

United’s new goalkeeper instantly raced over to remonstrate with Maguire, possibly because he viewed the pass to Eriksen as being too short. Martínez said: “It’s better for [this]. If you are focused you can fight with your teammates as well; you need to make sure everyone is really sharp, but nothing happened. It’s part of football.”

Martínez played with Onana at Ajax and offered an insight into the Cameroonian. “He has a big personality, he can play football, he can deal with the pressure,” he said. “He’s really positive, he’s a leader – that’s the style of Manchester United.”

Last season United finished third, 14 points behind Manchester City, their 58 goals the lowest in the top six, and won only eight of 19 away matches. Martínez was asked what United need to do to close the gap.

“We need to score more goals and we need to win more away games,” he said. “We need to read games better too. We need to read the situation, we need to be ready, be better and strong in the mind because football is mental.

“You can’t sleep [during games]. Sometimes, in one second, you can concede goals in the Premier League and you lose. We want to show something different this season. We are positive and we feel really strong.”