LONDON - Manchester United’s pre-season performances have been encouraging but rehabilitation under new manager Louis van Gaal begins in earnest on Saturday when they kick off the new Premier League season at home to Swansea City.

Dutchman Van Gaal, whose managerial haul includes league titles in the Netherlands, Spain and Germany, faces arguably his toughest task to date in restoring United quickly back to the top of English football’s pecking order.

United’s 20th league title in Alex Ferguson’s farewell season was followed by a slump to seventh - their worst showing in recent years as Ferguson’s successor David Moyes found himself horribly out of his depth.

The only way is up, it seems, under van Gaal, though how fast and how high depends on him quickly implementing his own style on a squad that still looks thin on a quality in several areas despite 56 million pounds of spending.

A home lunchtime clash with Swansea, starting their fourth season in the Premier League with long-serving defender Gary Monk now in charge, should give United temporary leadership of the table although champions Manchester City and Chelsea will be determined to put down early markers away from home.

City face Newcastle United on Sunday while Chelsea, with a parade of new signings including Cesc Fabregas and Diego Costa, have to wait until Monday to launch their assault on a first league title since 2009-10 away to promoted Burnley.

Like Van Gaal and Costa, Chile striker Alexis Sanchez will also get his first taste of the Premier League as Arsenal begin with a Saturday evening London derby against Crystal Palace.

Liverpool, runners-up last season, begin life after striker Luis Suarez at home to Southampton from whom they signed Rickie Lambert, Adam Lallana and Dejan Lovren with a chunk of the cash they received from Barcelona for the controversial Uruguayan.

Tottenham Hotspur begin yet another ‘new chapter’ at West Ham United with former Southampton boss Mauricio Pocchetino in charge while Everton, unlucky to miss a top-four spot last season having gleaned 72 points, visit promoted Leicester City.

United enjoyed wins against European champions Real Madrid and Liverpool during their north American tour and added a 2-1 victory against Valencia on Tuesday in their final warm-up fixture, after which striker Wayne Rooney was named as the club’s new captain in the wake of Nemanja Vidic’s departure.

QUICK FEET

With the onus on Rooney and fellow forward Robin van Persie to score the goals, United’s lack of central midfield flair, so apparent last season, could be solved by the quick feet of Ander Herrera who has signed from Athletic Bilbao.

Van Gaal knows a fast start will be vital to challenge last season’s top four and believes confidence is high as Swansea loom, although he also offered a cautionary note to the fans.

"They expect a lot and you can’t change everything in three or four weeks,” he said of the Old Trafford faithful who will have no European football to distract them this year.

"And the players can’t change either. We have to wait and see and develop. We need time but we have won every game up until now and that’s fantastic when you see our opponents. We have great confidence to play against Swansea City.”

While United are still expected to add to their ranks before the transfer window closes on Sept. 1, Chelsea and City appear to have concluded their main business.

Costa, whose goals fired Atletico Madrid to the Spanish title last season, scored twice in a 2-0 friendly win over Real Sociedad on Tuesday at Stamford Bridge in which Jose Mourinho played his likely starting team to face Burnley on Monday.

Mourinho, in the second season of his second spell in charge, believes Brazilian-born Spain international Costa will relish the physicality and pace of English football.

"It’s about his defensive work, mentality and ambition,” said the Portuguese coach, whose side shot themselves in the foot during the run-in last season.

One player who will not be pulling on a Chelsea shirt is midfielder Frank Lampard, who instead will feature in the light blue of Manchester City after one of the stranger pieces of transfer activity in the close season.

Lampard left Chelsea after 13 years in July to join MLS club New York City FC before being loaned to City for six months.

City, who also signed France centre back Eliaquim Mangala this week for 32 million pounds to go with his Porto team mate Fernando and Arsenal right back Bacary Sagna, will take some shifting from their perch.

"I am happy with the squad because I think we have a stronger squad this year than last year,” said manager Manuel Pellegrini, who side started slowly last season.