Back in the Netherlands, they will understand where Louis van Gaal was coming from when he broke from his normal position recently – and, let's face it, he never usually runs out of breath blowing his own trumpet – and warned it might be a few months before everything takes shape at Manchester United, judging by his experiences at previous clubs.

His pattern of slow starts goes all the way back to Ajax, the club he took to victory in the European Cup, when Van Gaal's early results were so undistinguished his biographer, Maarten Meijer, can remember the sports writers on De Telegraaf orchestrating a campaign for Johan Cruyff to take over and open hostility from the crowds at Stadion de Meer, Ajax's ground at the time. "Calls from the stands for Cruyff to return were interspersed with shouts of 'Van Gaal, get out.'" Van Gaal is hardly lacking what the Dutch call zelfverzekerd. "Louis is damn arrogant and we like arrogant people here" was how Ajax's chairman, Tom Harmsen, introduced him to his first coaching role, but even someone that headstrong was entitled to the odd flutter of insecurity. "That wasn't fun for me," Van Gaal reflected, almost two decades later.

There were some difficult times at Bayern Munich as well, before his first season in the Bundesliga, in 2009-10, culminated in his players chasing him around the pitch for the traditional victory beer-soak. It was Mark van Bommel who eventually caught him and emptied one of those three-litre tankards over his head, but Van Gaal had far more uncomfortable moments.

By late October, Bayern were eighth, enduring their worst start to the Bundesliga in 15 years, and there were strong rumours he would be sacked if they failed to win their next match. They were playing Eintracht Frankfurt and, with four minutes to go and the game level at 1-1, he did the unthinkable: replacing the striker Luca Toni with a defender, Martín Demichelis, and telling him to play up front. It was a gutsy move, but Van Gaal ignored the crowd's derision and Demichelis scored a season-changing winner with two minutes to go. After the timidity of the David Moyes era, when Sir Alex Ferguson's successor seemed to age in front of our eyes, United's supporters should embrace that story for what it says about the boldness of the new man.

Van Gaal certainly looks and sounds like a man who means business but, realistically, if the question is whether he can assemble a team that is capable of challenging Manchester City and Chelsea this season there are limits to what should be expected. No team has won the league after finishing seventh the previous year since Everton in 1985 and there is an awful lot of ground for United to make up. City finished 22 points ahead of them last season with a goal difference (plus 65) that was higher than the entire number of goals their neighbours had managed (64).

City's last defence of the title two years ago smacked of a team that had lost their focus – "They settled into a sense of relief," as Ferguson put it – but that was in the febrile atmosphere of Roberto Mancini's final year in Manchester. Manuel Pellegrini has changed the mood of the club and nobody should really jump to too many conclusions about one prosaic display in the Community Shield.

It is certainly easy to imagine the trophy will be adorned in blue ribbons next May, though not so simple trying to predict whether they will be of a light or dark variety now Chelsea have adjusted more to José Mourinho's liking with the recruitment of three outstanding players – Diego Costa, Cesc Fábregas and Filipe Luís – as well as Didier Drogba's second coming and Thibaut Courtois' return from his loan arrangement at Atlético Madrid.

Chelsea, like City, have had to operate with more restraint than they would ordinarily like this summer, in keeping with the financial fair play strictures. Equally, we should know enough about Sheikh Mansour and Roman Abramovich to understand that asking them to watch their spending is a bit like telling Paddington Bear to lay off the marmalade.

Chelsea in particular have had a productive summer and the mind goes back to a tribute dinner for Mourinho at the Savoy last January, when Van Gaal was one of the guest speakers. "I am always the 'arrogant Louis van Gaal' but now I am humble," he said, turning towards the Chelsea manager. "I used to say I was the best. Now, he is better than me." Mourinho, with nothing to show for his first season back at Stamford Bridge, needs to remind his club they have employed a trophy machine. In those circumstances, he normally delivers.

Arsenal may yet be authentic challengers to English football's two most financially endowed clubs and Alexis Sánchez should fit seamlessly into a team that had longer at the top last season than any other. Yet the league is a test of endurance and there are still lingering questions about whether Arsène Wenger's team are streetwise enough.

Would they cope, for example, with an injury in central defence if their only real cover comes in the form of the talented but raw Calum Chambers? Arsenal have the best assortment of attacking midfielders in the country but they can also be overly reliant on Olivier Giroud. The FA Cup winners should be invigorated by ending that nine-year stretch without a trophy, with all the associated stresses, but it would enhance their chances considerably if Wenger could recruit another defender and striker before the transfer window closes.What can be said with certainty is that it should be one heck of a battle around the top six bearing in mind the number of teams approaching the new season on an upward trajectory. Everton, under Roberto Martínez, will harbour ambitions of improving again from last season, when they recorded a record number of points in the Premier League era.

Tottenham Hotspur will like to think they can get closer to the top after the appointment of Mauricio Pochettino and, though Van Gaal has traditionally started sluggishly with all his previous teams, he has certainly been handed an obliging opening run of games compared to the challenges that confronted David Moyes this time a year ago, when United had City, Chelsea and Liverpool among their opening five games. Moyes always suspected the fixtures were set up that way to reduce the threat of United, the runaway champions, turning the league into another procession, and to provide some big live games early on in the first season of rivalry between Sky and BT Sport. Whatever the truth – and the relevant authorities deny his version of events – the bottom line is that Van Gaal has been given a much more straightforward entrance. His team really ought to get off to a flier when their first six games are against Swansea, Sunderland, Burnley, Queens Park Rangers, Leicester and West Ham and it is not until October they face a team, Everton, that finished in the top five last season.

As for Liverpool, the popular belief is that their forward momentum will fall away now that Luis Suárez, the best player in the league last season, has left for Barcelona. There is a good chance that may happen, too, judging by the deterioration at Spurs after Gareth Bale's departure or the way United were never so formidable once Cristiano Ronaldo left. Teams rarely improve after they have moved on their outstanding player, no matter how much money it frees up, and in Suárez's case that was a nice line doing the rounds recently about it being the equivalent of selling an iPhone then splashing out on a pager, a phone, a fax machine, a camera and a pen.

Liverpool have won plenty of matches without Suárez but Brendan Rodgers also has to factor in the extra rigours of Champions League football. Those demands can be telling and the likelihood is it will end with the Anfield club clocking up 25 years since their last league championship.

At the other end of the table, Burnley may have to grit their teeth and grow accustomed to being assigned one of the relegation places in every newspaper's predictions section (while consoling themselves with the thought that everyone reckoned the same about Hull City last season). For Hull and Crystal Palace, it is all about avoiding second-season syndrome, and the London club immediately look more susceptible now Tony Pulis has gone.

Leicester, the runaway winners of the Championship, have a vibrancy to their team that means they should not be too fazed by the challenge of showing they belong at this level. QPR, however, might find it more of a challenge while it could be another difficult season for West Brom, Aston Villa, West Ham (and Sam Allardyce) and the two north-east teams.

Swansea might also be vulnerable and it is just a pity for Ronald Koeman, Southampton's new manager, that the break-up of Pocchetino's team, after being one of the success stories of last season, also puts them in the category where they might be at risk. "We are definitely not factoring in a big player sale," Ralph Krueger, Southampton's chairman, said in April. He actually sounded like he meant it, too. The club maintain it is not a fire sale but they might still be badly burned.