Louis van Gaal is somehow clinging onto his job for now but most expect the under-fire Manchester United manager to be replaced by Jose Mourinho at the end of the season.

The Portuguese's anticipated arrival should coincide with the most expensive transfer window to date at Old Trafford; the current Red Devils squad still lacks top-class quality and the new TV deal should see Premier League clubs spend like never before.

Mourinho will find that particularly pleasing. Although there is no doubt over his ability to obtain silverware, his trophy hauls are often accompanied by prolific spending in the transfer market, bringing in the biggest talents Europe has to offer.

So with that in mind and the summer transfer window by no means as far away as it may seem, here are FIVE superstar signings to kick off the Jose Mourinho era at Old Trafford.

MATS HUMMELS

Hummels

Not a transfer window goes by without Manchester United being dubiously linked with a bid for Mats Hummels, but the coming summer represents their best chance to date of luring the World Cup winner away from Borussia Dortmund - when his Westfalen contract will have entered its final twelve months.

The Red Devils require a long-term partner to Chris Smalling, with utility man Daley Blind filling the void at the heart of defence this season, and the German international certainly fits the bill, famed for his Beckenbauer-esque ball-playing instincts and widely considered one of the top centre-halves in world football.

Indeed, the 27-year-old has featured in World Cup and Champions League finals whilst lifting two Bundesliga titles and has captained the Black-Yellows since the start of last season. But the Hummels-to-United transfer saga has dragged on for so long that most Red Devils fans have probably given up all hope of him actually turning up at Old Trafford.

Antoine Griezmann

Antoine Griezmann

Antoine Griezmann was continuously linked with a Chelsea transfer throughout Jose Mourinho's second spell at it's not hard to see why; the Frenchman has flourished under Diego Simeone's likeminded philosophy of organised pragmatism, bagging 49 goals in 94 appearances for the Mattress Makers.

Manchester United lack firepower up front and quality out wide but the 25-year-old's arrival could address both issues in one fell swoop. In addition to emerging as one of La Liga's most potent frontmen at Atletico, his performances as a winger for former club Real Sociedad often verged upon talismanic.

Famed for his tenacity and stamina, Griezmann has often been mooted as a particularly good fit for Premier League football. But Atletico are desperate to keep hold of their star asset ahead of their twelve-month transfer ban and are working to raise his release clause to a whopping £79million.

ZLATAN IBRAHIMOVIC

Zlatan Ibrahimovic (2)

They don't get much more star-studded than Zlatan Ibrahimovic, who looks set to leave PSG on a free transfer at the end of the season.

Indeed, the notoriously enigmatic Sweden international hasn't lost a title race since 2003, spanning spells with Ajax, Inter Milan, AC Milan, Juventus, Barcelona and the Parisians - firing his current employers to four consecutive Ligue 1 honours with 141 goals in 169 outings across all competitions.

Zlatan may not offer much longevity at 34 years of age but pace has never been his forte and the 6 foot 5 striker is still producing the goods in front of goal, so a short-term deal could prove to be an incredibly shrewd move on United's part.

There are already rumours of a preliminary discussion with Jose Mourinho regarding a potential Old Trafford transfer, but the veteran front-man's wages are astronomical and he's always been a rather controversial character.

JAMES RODRIGUEZ

James Rodriguez

James Rodriguez emerged as one of the beautiful game's top talents upon claiming the Golden Boot award at the 2014 World Cup but his subsequent move to Real Madrid hasn't exactly gone as planned, struggling for fitness and form particularly this season.

Nonetheless, the attacking midfielder is an exciting player who combines creativity, technical flair, firepower and a stocky frame that should put him in good stead for the physical challenges of the English top flight. Likewise, a return of 19 goals and 18 assists in 48 La Liga outings is certainly nothing to be sniffed at.

Rumour has it Real Madrid will look to offload the Colombian international this summer and barring a move to Bayern Munich, the Premier League remains his most logical next destination. However, Los Blanos will expect to recoup the vast majority of their original €80million investment and the 24-year-old's underwhelming form this season is a significant concern.

PAUL POGBA

Pogba

Paul Pogba looks set to enter the summer transfer window as arguably the most sought-after player in world football, so bringing him to Manchester United will be a real signal of intent on Jose Mourinho's part.

The Juventus ace has emerged as one of the best in the business since swapping Old Trafford for the Old Lady in summer 2012, placed somewhere between Yaya Toure and Patrick Vieira on the goalscoring enforcer spectrum through his mix of netting prowess, technical skill and ranging physicality.

The France international rejected widespread interest last summer - including from Jose Mourinho's Chelsea - but is likely to be on the move during the coming transfer window following yet another title campaign in Turin and the European Championship on his home soil.

But Juve still expect to pick up a fee in excess of £65million for the 23-year-old and with so many major clubs interested, not least including Barcelona and Real Madrid, United could find themselves some way down the pecking order.