Anthony Martial's dramatic start to his Manchester United career continued as he scored twice in a 3-2 victory at Southampton on Sunday that left his side second in the Premier League table.

Last weekend Martial, 19, made an immediate impression in his first appearance since his move from Monaco for a reported initial fee of £36 million ($55 million, 49 million euros) with a superb debut goal against Liverpool.

He followed that up with two more impressive finishes that allowed United to overturn Graziano Pelle's 13th-minute opener.

Juan Mata wrapped up the win in the 68th minute, with Pelle's second goal coming too late to affect the outcome.

After an unconvincing start to the game, United responded to claim a valuable win that moved them to within two points of leaders Manchester City, with the performance of Martial in particular offering the promise of more to come from Louis van Gaal's side.

Southampton, on the other hand, are still struggling to develop momentum this season and manager Ronald Koeman will be concerned at the way his side fell away after holding the early initiative.

With Luke Shaw facing months on the sidelines after suffering a double fracture of his right leg during the mid-week Champions League defeat at PSV Eindhoven, United manager Van Gaal handed Marcos Rojo his first start of the season at left-back.

The Argentina defender incurred his manager's anger when a passport problem prevented him from boarding a flight to join up with the club on their pre-season tour of the United States.

This, therefore, was an opportunity for Rojo to show he deserves an extended run in the team, but like the rest of his colleagues, he took time to settle.

Southampton's high press forced a succession of errors that eventually led to Pelle's goal and could have seen Van Gaal's side three goals down before Martial scored.

Morgan Schneiderlin was making his first return to St Mary's since his £25 million move to the northwest, but the France international, operating in front of the back four alongside Michael Carrick, found himself overwhelmed by his former team-mates.

That exposed centre-backs Chris Smalling and Daley Blind to the energy of Sadio Mane, himself a reported United target, and the well-timed runs of Pelle, while Rojo was having a tough time handling James Ward-Prowse.

It was no surprise that Southampton's breakthrough came from their right flank.

Rojo was caught out of position, allowing Ward-Prowse to whip in a cross towards Mane, whose volley was saved superbly by David de Gea before Pelle followed up to score.

The Italy striker could have had a second goal moments later when Mane's persistence forced an error from Smalling and Pelle drilled a shot against the post.

Martial looked isolated up front, until his team-mates finally began to establish a foothold in midfield.

Then, after an extended period of possession, the striker was presented with the opportunity to level in the 34th minute, creating space inside the penalty area with a superb turn before calmly finishing.

Martial's composure was striking and in evidence again when he moved onto Maya Yoshida's under-hit back-pass five minutes into the second half and coolly side-footed past Maarten Stekelenburg from 20 yards out.

Southampton's collapse had been alarming and when they did fashion another chance, De Gea produced a second outstanding one-handed save, this time to beat away Jose Fonte's near-post header.

That was a rare threat from a side whose belief appeared to have disappeared and it was no surprise when Mata added a third, striking from 16 yards after Memphis Depay's powerful shot cannoned back off the post.

Pelle gave Southampton hope when he headed past De Gea from Mane's cross, but the goalkeeper was on hand to keep out Victor Wanyama's long-range effort and preserve the visitors' advantage.