Lisandro Martinez has told Manchester United’s new goalkeeper Andre Onana to keep on rollicking his defenders.

Harry Maguire copped an earful from Onana during the second half of United’s 3-2 friendly defeat by Borussia Dortmund in Las Vegas on Monday.

Onana tore into Maguire after the England defender had wrongly left the ball during a mix-up with Scott McTominay that ended up with the Cameroonian goalkeeper being forced to make a diving save to deny Sebastien Haller.

Onana has only been at United for a fortnight after signing from Inter Milan for £47 million but David de Gea’s replacement in goal has already shown he is unafraid to bark orders at team-mates and admonish them when required.

Martinez played with Onana at Ajax and says United have signed a big character as he encouraged the goalkeeper to keep speaking his mind.

“It’s better for [it],” the Argentina centre-half said. “If you are focused, you can fight with your team-mates as well. You need to make sure everyone is really sharp, but nothing happened. It’s part of football.

“He has a big personality, he can play football, he can deal with the pressure, he’s really positive, he’s a leader. That’s the style of Manchester United.”

Maguire was stripped of the United captaincy by Erik ten Hag this summer and replaced by Bruno Fernandes, and Martinez – the club’s first choice centre-half along Raphael Varane – said it was important the manager’s decision was respected.

“It’s the coach’s decision and we need to respect it. He’s the boss,” Martinez said. “If he takes the decision, as a player we need to keep going. Bruno is a good leader and a good person as well. He’s really positive in the dressing room and I think he deserves it.”

Martinez missed the final 12 matches of last season after suffering a broken metatarsal in the 2-2 Europa League draw at home with Sevilla.

But he has shown no signs of holding back since returning to action in pre-season and was booked for bone-crunching challenges on Buyako Saka and Jude Bellingham during games against Arsenal and Real Madrid in the US.

“When I play football, I give everything,” he said. “I play like this – with passion – because when I look at the badge, I represent this club and it’s amazing.

“All I can give is my body and my heart and everything. I represent this club with my all and I hope all the players do as well. I feel stronger than last season and I think also the team wants to show something different when the league starts so we are fully positive and feel really strong.”

Some United fans have wondered if the team would have had a better finish to last season had Martinez not succumbed to injury with United losing the FA Cup final to Manchester City and crashing out of the Europa League in embarrassing fashion.

Martinez is too humble to suggest as much but says United must become more clinical in front of goal, stop the sudden collapses they have experienced and improve their disappointing away record next term.

“For sure, it’s really hard when you are out, when you can’t help the team but it is what it is and things happen for a reason,” he said.

“Now we need to learn, we need to improve many things. It’s part of the process and I think this club will make a lot of success.

“I think we need to score more goals and also our away games – we need to win more away games. I think we need to read the games better. We need to read the situation well, we need to be ready and we need to be strong in the mind because football is mental.

“When you are losing, sometimes – in one second – you can concede many goals in the Premier League. You can’t sleep but we want to show something different this season.”