Focus on Erling Haaland v Lisandro Martinez battle in Manchester derby

Diminutive defender takes on prolific striker at the Etihad Stadium on Sunday

Manchester United's tenacious defender Lisandro Martinez will face the ultimate test when he takes on Manchester City striker Erling Haaland who will be looking to extend his red-hot streak in Sunday's derby.

Haaland has made a sensational start with City since joining the Premier League champions from Borussia Dortmund for £51 million.

The Norway striker has accumulated 14 goals in nine games in all competitions for City and will run into a rejuvenated United who sparked a turnaround in the league after a poor start.

When Erik Ten Hag was managing Ajax against Dortmund in the Champions League last season, he stopped Haaland from scoring and won the group match thanks in large part to an inspired display from Martinez, who is now at United.

Ten Hag brought Martinez with him to Old Trafford and the 24-year-old is already producing commanding performances.

However, at 6 feet 4 inches, Haaland will tower over Martinez, who is the Premier League's smallest centre back at 5ft 9in.

But the aggressive Argentine has gained a reputation of taking on opposing strikers. Martinez has already earned cult hero status among United fans with some ferocious tackling.

Partnering with Raphael Varane in central defence after Harry Maguire was dropped two games into the season, Martinez has shored up a unit that was United's Achilles heel last season. United have won all five games in which Ten Hag has played Martinez and Varane together at the heart of the defence.

Ten Hag called the Argentine a "warrior", lauding his "attitude and fighting spirit".

But he knows keeping Haaland off the scoresheet at the Etihad Stadium will be a tall order if Martinez does not get enough help from his team-mates.

"We don't play against Haaland, we play against Man City," said Ten Hag. "We are convinced of our capabilities. If we act as a team we can beat our opponents.

"We need to look to ourselves. We have to perform at our best, with a good game plan. Then it is about execution. We will have to do 100 percent."

City boss Pep Guardiola is well aware that Martinez could pose a formidable challenge to Haaland.

Guardiola said: "Erling is taller, that is for sure, but I like it when the people underestimate a football player just for his size.

"He can tell them: 'I am here, I am a good player, I can play everywhere'. He's a fantastic player - incredible in the build-up, good mentality, aggressive.

"It is not the first time he [Martinez] has played against strikers who are taller than him and he handles it.

"Of course, the crosses into that position, Erling is taller, but we will see what happens."

Meanwhile, Guardiola has praised his medical staff for keeping Haaland fit. Despite boasting a prolific record throughout his young career, the 22-year-old has also had a number of injury problems.

Yet with Haaland having so far started every game for City, Guardiola is hopeful they are now a thing of the past.

The City boss said: "Everyone is important but I've always said to the club that the most important department in the backroom staff is the physios. They take care of the legs.

"Erling struggled a lot in Dortmund last season with injuries and arrived here with little problems after a small surgery in the summer.

"He started to work here with [physiotherapist] Mario (Pafundi) and the other guys and thanks to them - and of course his work ethic - he can play regularly now. Last season it was not possible.

"When the players can play most of the time it's thanks to the physios."