As a family friend and someone who covered his every move as a TV reporter in Germany, Rosler is well-placed to discuss Haaland. He also enjoys cult status at City after a four-year spell.
‘Nobody has ever seen anything like this,’ he said. ‘He hardly misses a one-on-one. All angles, different speeds. Players become inaccurate with their final ball at top speed but not him.
‘Look at Messi and Ronaldo. They didn’t develop like this. They didn’t have the goals per game at this age. In terms of that, there is nobody who can match him – especially when we talk about the Champions League.’
Haaland has 23 goals in that competition, for Dortmund and Red Bull Salzburg, at a rate of one every 64 minutes. And we all know City’s recent history in Europe.
‘Such an intelligent player,’ Rosler adds. ‘Dortmund played vertically, looking for runs from Erling in behind and his timing is a very strong attribute. He is hardly ever offside – I’ve never seen that in someone so young.’
Norway head coach Stale Solbakken, who has seen him score a goal a game, agrees. ‘Never offside. Amazing, amazing.’
Expectation has forever followed Haaland, from learning under Ole Gunnar Solskjaer at Molde to a whirlwind 12 months at Salzburg initially with Marco Rose – later to become his manager in Germany – and Jesse Marsch, who oversaw a stunning goal return.
Around Dortmund they talk about the physical difference in Haaland over an astonishing two and a half years.
The striker looked strong on his competitive debut against Liverpool in the Community Shield
In winter 2020, I saw a small guy – the muscles weren’t so big, baby face, short hair – and now he is like a monster I’d estimate he has put on 10 kilos more in muscle,’ one source says.
Still growing, too, with suggestions around City that he may have become slightly taller since signing two months ago. Often in the gym, Haaland might give fanatic Ruben Dias a run for his money.
Those who know him say there is a purpose to everything. John Haddad, his Lebanese personal trainer, worked him hard at the Marbella football centre over the summer as the family vacationed at their second home on the Costa del Sol.
He has thrown himself into yoga. There is the strict regime of refusing to use any technology two hours before he sleeps and, once the sun sets, on go orange-tinted blue-light filtering glasses, contributing to a restful night.
Haaland admitted last week that he is ‘not perfect’ fitness-wise, with City holding him back from the first few days of pre-season training to work individually. He missed 16 matches through various problems last term.
Haaland began playing senior football at the age of 15 with Norwegian second-tier side Bryne
Another question mark is around Guardiola’s defensive shape, but Solbakken offered an insight into how Haaland can manage relentless pressing.
‘I’ve made his defensive duties very concrete – specialised and specific,’ he tells Sportsmail. ‘We don’t let him off because Norway will never be good enough to defend with 10 men.
‘He has tremendous speed. I tell him that if he does six or seven quick yards against the goalkeeper or defenders, it makes a big difference. He doesn’t have to work over 20 or 30 yards if the distances are right in the team behind him and he can put pressure on quickly.’
Short, sharp bursts are what we saw against Bayern, aggressive running in the opposition’s third and City regularly turning over possession – often to the benefit of Kevin De Bruyne.
At his unveiling, Haaland maintained that he can improve ‘everywhere’, a definitive answer from someone eager to learn under Guardiola. At Dortmund, they have seen proof of his desire to better himself, with Rose playing a major role last term.
He has since grown to 6ft4ins in height and added 10 kilos in muscle to turn from boy to man
‘When you are 1.95m (6ft 4in), your head can be a really strong weapon,’ Rosler says.
‘I spoke to Marco Rose and they focused on that. You can see the success. Last season he made a big step with his presence in the box.’
Rose’s assistant, former Bayern striker Alexander Zickler, spent hours at the Brackel training ground with Haaland. Movement was key, as well as honing his ability to strike off his weaker right foot.
‘Alex was someone who Erling looked up to,’ a source reveals. ‘He said, “I haven’t won the championship a single time and he has won it multiple times”.
‘Alex worked on the right foot, headers and so on. If you take a look at how he scored his goals in year one, then 80 or 90 per cent come from the left foot. In year two there were far more goals by headers and with the right foot.’
In significantly fewer games, headed goals went from one to five, right-footed strikes from three to four. Some work is still required, however, after Haaland missed when going with his preferred left peg rather than simply heading home during the Community Shield defeat by Liverpool.
His career trajectory has been meticulously planned.
‘Team Haaland’ are a small but dedicated group who have, without fail, perfectly chosen each destination since the striker left the small south- western farming town of Bryne, with a population of 12,000, five years ago.
Molde was a 13-hour drive north. Not exactly nearby.
His father, former City captain Alfie, felt that the life lessons learned away from home comforts would be equally as valuable as working with fellow striker Solskjaer.
Norway boss Stale Solbakken (right) has called him the most famous Norwegian athlete ever
Juventus were rejected when they came calling in 2019, with Salzburg offering a more obvious pathway.
Rose made him wait for his chance in Austria but he soon exploded under Marsch and Dortmund saw the benefits of landing him with a £51million release clause inserted. There is at least one release clause in his City contract too, with suggestions of at least three times that price.
Alfie, believed to have been an Arsenal fan as a child, is aided by lawyer Rafaela Pimenta, who worked with agent Mino Raiola before his death in April.
Friend Ivar Eggja, who Haaland calls his uncle, was also present at his City unveiling. Former Southampton, Blackburn and Norway striker Egil Ostenstad went into banking and is thought to advise on Haaland’s finances.
Bryne is fiercely proud of his achievements and there are murals of him around the town. Only 22 earlier this month, here stands a national icon.
‘We have Olympic champions in the 1,500m and 5,000m but it is fair to say that he is the most famous athlete that Norway has ever had,’ Solbakken said. ‘We have to take a little bit of extra care of him with the national team.
Haaland has a phenomenal record of 20 goals in 21 games for his international side (above)
‘But at the same time, he has to take more responsibility because he is our key player. We treat him normally – it is something he enjoys. He is part of the jokes and the everyday life. There is always an extra eye on him and we try not to make it a circus.’
Zlatan Ibrahimovic is a name which continually crops up when discussing Haaland. The style, the persona in front of the cameras. ‘Sometimes I felt he wanted to be a bit like his idol, Zlatan, a little bit cool,’ a source says. ‘But everyone in the dressing room liked him.’
Haaland, close friends with Jude Bellingham, gifted every player and backroom staff member a £5,000 Rolex when he bid farewell to Dortmund in May. He asked the club to give him one final day in the city to ‘create memories’ and say goodbye. The emotional exit was described as ‘spectacular’.
The Haaland Song – written by Dortmund supporters and including the line ‘a superboy from outer space’ – has followed him to Manchester. City’s players, who really took to their new No 9 on tour, serenaded him with it before he gave a short speech at dinner in Houston.
His initiation song, Hero by Enrique Iglesias, went down a storm – although Kalvin Phillips ultimately took the plaudits with George Ezra’s Budapest.
City have already noticed his burgeoning relationship with winger Jack Grealish (pictured left)
The esteem in which Haaland is held was also evident inside the Norway dressing room after they beat Sweden in a competitive match for the first time since 1977. He scored both goals in a 2-1 win in June and captain Martin Odegaard reached for the speakers, blasting out the Haaland tune.
Solbakken says Haaland, one of his vice-captains, is a popular player. ‘What I like most with him is that he measures himself in goals but he really enjoys playing the assist,’ he said.
‘He enjoys putting team-mates into a better position and you will never ever see him shoot when he should pass. He always takes the better option. His joy for his team-mates when they score is very real, it is not acting. It makes him likeable.
‘When you have a physique like one of the best galloping horses, this hair and natural charisma…he is a team player when everyone else is screaming for goals. You see that on his face.’
There was an immediate connection with Jack Grealish, the pair ‘buzzing’ with each other down the Lambeau Field tunnel after combining for the only goal against Bayern. Guardiola cannot fail to have taken note of the link-up and camaraderie.
‘His physique is unique in that his first metres are very quick, then the height – it’s a big advantage,’ Solbakken adds. ‘Especially with counter attacks. And then when City play their small passes around the box he can explode in the small areas.
Haaland has a special place in his heart for Leeds United, the place of his birth, but City has felt like his destiny for some time. He was even in a Norwegian City supporters’ page on Facebook until his silent participation leaked out beyond the private group.
He was initially invited in by Halvor Hoevring, a City fan who first saw Haaland live when facing his brother’s team, Akra, in a second division fixture in 2016. He came on as a half-time substitute and changed the game that day.
‘We’ve always known he was a City fan,’ Hoevring says. ‘Some liked him more over here when he played for Dortmund because a lot of people don’t like City. There are so many Manchester United and Liverpool supporters.
‘A lot of people were surprised how quickly he became a superstar but everyone knows now that he is one of the greatest in the world.
‘When he played for Molde, I remember the club chef said that Erling always ate more than the others. That will continue at City! He has already told the cooks that they will be his best friends.’
Guardiola invited all of City’s travelling party to Texas seafood restaurant Willie G’s as a bonding exercise. Who knows how much Haaland ate that night, but the smorgasbord of chances that are coming his way ought to have him salivating.