Cape Town - He shocked the world on his debut for English giants Manchester United.

In September 2015, a then 18-year-old Anthony Martial completed his move from AS Monaco to the Red Devils on a four-year, £36 million deal.

United manager at the time, Louis van Gaal, recruited the teenager, but several football enthusiasts were left wondering who this young Frenchman was.

Martial duly silenced his sceptics, letting the footballing world know who he was after being given the chance to come off the bench against United's greatest rivals, Liverpool.

It took Martial no more than 20 minutes to ensure his name would hog the headlines the following day as he carved his way through the Liverpool defence with Martin Skrtel left to rue his decision to leap in for a tackle as Martial turned inside with finesse and struck a low shot into the bottom corner, making it 3-1 to United.

Martial followed that up with a brace in United's next match against Southampton and then netted his fourth goal against Ipswich Town a week later.

Plaudits rolled in from football pundits and fans on social media, but a little over four years later, Martial's career at United has taken an worrying turn.

Winger or striker?

Current coach Ole Gunnar Solskjaer has entrusted the 24-year-old to lead the attack as United's out-and-out striker this season.

However, it has not all worked out favourably, despite his 12 goals in 28 matches (in all competitions).

Martial was forced to miss nine matches due to a hamstring injury which saw him sidelined for 56 days (August 25 to October 20) while in early December he was out with illness for three days where he missed one match.

The injury and sickness may well have contributed to his recent underwhelming performances this season - or could it be his position?

Prior to the start of the 2019/20 campaign, Martial was often deployed on the left-wing where he enjoyed much success, scoring 34 goals and nabbing 24 assists.

The Frenchman played 109 times down the left flank while he has also been asked to play on the right-wing on 10 occasions.

In 45 appearances as a striker he bagged 11 goals and seven assists.

Martial has moments where he is in sync with his team-mates and where it seems every decision he makes with the ball at his feet could lead to a possible goal.

However, it has just not happened often enough this season as he struggles to perform consistently.

Former United manager Jose Mourinho usually deployed the Frenchman on the wing, but, to his dismay, he was often playing off the bench due to his lack of defensive work in tracking back - an integral part of Mourinho's tactics and modern football.

"I know that Martial likes to play as a No 9 (striker), sometimes I think for the right reasons, sometimes I think for the wrong reasons, but I know he likes to play as a No 9," Mourinho said on Sky Sports following United's 4-0 win against Chelsea in August last year.

Pressure from Odion

The recent January transfer window saw United sign midfielder Bruno Fernandes from Sporting Lisbon.

United also handed a Premier League return to former Watford striker Odion Ighalo on a six-month loan.

The Nigerian's arrival is something of a warning sign for Martial, but also precautionary as United are short in the striking department.

Marcus Rashford is out with a back injury with his return date still unknown, while 18-year-old Mason Greenwood has so far impressed, but Solskjaer has often spoken of protecting the teenager with moderate involvement.

And now with the two-week winter break - which could well have come at the perfect time for Martial - the Frenchman needs to grasp the opportunity when the season resumes to ensure Solskjaer doesn't opt to turn to Ighalo as his main man.

When the Premier League does get back underway, United travel to Chelsea (Monday, February 17), with the Red Devils desperate for points.

United are currently seventh in the standings, a yawning 38 points adrift of runaway log leaders, Liverpool.

This season has seen Martial miss at least six clear-cut scoring chances in front of goal which could easily have changed the dynamic of United's season.

Of his 48 attempted shots on goal this season, only 24 have hit the target, giving the Frenchman a 50% shooting accuracy.

These figures are not a total shocking, but the talented forward would want to see those numbers improve. 

However, if things continue to prove bleak for Martial, he could well end up playing his football elsewhere next season.