Many feared for Manchester United's firepower after parting with Robin van Persie and Radamel Falcao earlier in the summer and those concerns have been validated by the Red Devils' poor start to the season in front of goal, netting just twice in their opening four Premier League fixtures.They fared considerably better against FC Brugge in the Champions League - winning the double legger 7-1 on aggregate - but without further additions between now and the transfer deadline tomorrow, United's chances of claiming the English crown for the first time since Sir Alex Ferguson's retirement will plummet further towards zero.That being said, anything seems possible during the final days of the summer window, so there's still time for the Old Trafford outfit to get a deal or two over the line.And just in case Louis van Gaal isn't too clued up on realistically available striking options as the 6pm deadline looms in, we've outlined FIVE centre-forwards who could still be open to a last-minute Old Trafford switch.

ANTHONY MARTIAL

According to reports from The Daily Mail yesterday evening, Manchester United have lodged a £36million bid for Monaco's prodigious centre-forward Anthony Martial - who some have dubbed 'the new Thierry Henry'.

The 19 year-old's goal record for the Ligue 1 outfit isn't exactly outstanding, thus far netting just 13 times in 57 appearances across all competitions. But he developed at a phenomenal rate over the course of last season, whilst his strike-rate for France across the junior levels is an impressive one-in-two.

Blessed with an abundance of power and pace and particularly direct in style, a move to the Premier League seems to be the next logical step in Martial's career. Likewise, his ability to penetrate opposition defences will be of huge benefit to a United side who desperately lack threat in behind.

But whether highly-rated youngster is ready to join a title-contending Man United outfit remains open to interpretation. Likewise, Ligue 1 journalist Matt Spiro believes the Red Devils will have to offer significantly more to convince Monaco to sell:

SAIDO BERAHINO

Saido Berhaino has made his ambitions to leave West Brom for a bigger club abundantly clear this summer, handing in a transfer request at the Hawthorns following a £19million bid from Tottenham Hotspur earlier this month.

The Lilywhites appear to have now dropped out of the race to sign the 21 year-old, however, instead focusing their time and finance on a £22million deal for Bayer Leverkusen's Son Heung-Min, which gives the Red Devils a fantastic chance to not only improve their strike-force but also add to their ever-important home-grown contingent.

Indeed, with the exception of Harry Kane, Berahino is the most exciting striking prospect within the Three Lions' sphere of influence at this moment in time, netting 14 times in 38 Premier League appearances last term and boasting the third-most goals for England throughout the U21s' history - his haul of ten only bettered by Alan Shearer and Francis Jeffers.

The 21 year-old's ability to play out wide will particularly excite 'multifunctional footballer' enthusiast Louis van Gaal, whilst - much like Anthony Martial - Berahino's blend of blistering pace and poacher instincts represents precisely what United's forward line currently lacks.

Despite publicly insisting otherwise, it's believed Tony Pulis' side are willing to sell after securing the services of ex-Zenit front-man Salomon Rondon - but only if their £30million valuation is met.

GONZALO HIGUAIN

Speculation linking Gonzalo Higuain with a move away from Napoli has decreased in recent weeks. But with a release clause inserted into his contract, albeit one of £67million, Manchester United could still sign the Argentina international if they're willing to cough up the cash.

The 27 year-old is best famed for his netting prowess, having produced a career return of 223 goals in 497 appearances throughout his spells with River Plate, Real Madrid, Napoli and the Argentine national team.

But he's a more complete attacker than many would assume, racking up eleven assists in 52 outings for Albiceleste and 15 over the last two campaigns in Serie A. In fact, he spent much of last season playing on the wing under Rafa Benitez.

Following their failure to qualify at the end of last season, Higuain will be European football's most talented and proven striker not plying his trade in the Champions League this term.

That, in addition to the former Bernabeu star recently rejecting a one-year contract extension, suggests he would be interested in a last-minute switch to Old Trafford.

Whether United can justify activating Higuain's release clause, however, which would make him the most expensive player in Premier League history, is certainly open to debate.

ALEKSANDR KOKORIN

By no means an out-and-out centre-forward but nonetheless an attacking option that would add firepower to United's frontline - and according to the tabloids, one that the Red Devils have already approached regarding a last-minute move.

Cyril Loginov, agent of Dynamo Moscow forward Aleksandr Kokorin, declared last week; "Right now I’m working on Kokorin’s transfer. United and Tottenham are interested in his services. There are many reasons to think that it will [happen] in one of two teams before August 31."

The 24 year-old isn't exactly notorious outside of the Russian top flight but he comes highly-rated and has been in strong form over the last three seasons, amassing 29 goals in his last 74 league outings - including a return of two in three this term.

He was also one of the rare positives to come out of Russia's World Cup campaign last summer, scoring in a 1-1 draw with Algeria and consistently providing spark in attack throughout the Group Stages.

Due to his contract expiring at the end of the season, it's believed Kokorin could leave the Russian capital outfit for as little as £8million. Over the last few days, however, Arsenal have emerged as the 5 foot 11 forward's likelier suitors.

ZLATAN IBRAHIMOVIC

It's a transfer story the tabloids have continuously speculated on throughout the summer with various degrees of conviction. This late in the transfer window, a Manchester United bid for Zlatan Ibrahimovic seems somewhat unlikely yet the magic of deadline day refuses it to be ruled out completely.

Needless to say, the Sweden international is one of the greatest strikers of his generation, combining the elegance of Dimitar Berbatov with the power and 6 foot 5 frame of a towering target man to produce a career return of 396 goals in 723 appearances.

He's also a natural born winner, claiming league titles throughout his spells with Ajax, Juventus, Inter Milan, Barcelona, AC Milan and current club PSG, and in fact hasn't lost a title race since the 2002/03 campaign. Quite a phenomenal record.

The 33 year-old has admitted working with Louis van Gaal - especially after dissing the United boss in his latest autobiography - might prove difficult, due to both possessing rather sizeable egos.

But Peter Schmeichel believes Ibrahimovic was born to play for Manchester United and I firmly agree. Likewise, we know PSG don't intend to extend his contract beyond next summer - so one assumes they'd be willing to sell if the price is right.

How you actually value a 33 year-old who bagged 30 goals in all competitions last season, however, is a lengthy debate in itself.