By Manchester correspondent Alex Stevens

Anthony Martial does not look so overpriced now, Wayne Rooney is still labouring and other things we learned from Southampton 2 Manchester United 3.

Martial has ignited United with his pace and running power

What a difference the 19-year-old has already made.  Who expected him to be this good? Two Premier League matches have yielded three goals for Martial and, more significantly, ignited a previously one-paced, one-dimensional team. After his wonderfully composed finish minutes after coming on as a substitute against Liverpool, the Frenchman produced another couple of neat strikes at St Mary’s Stadium, equalising with United’s first shot on target and then taking advantage of a terrible Maya Yoshida backpass to slot in a second. After 18 months without a striker capable of running behind defences, United now have a great weapon up front. At £40million rising to a potential £58million, he does not looked so overpriced now. Indeed, if he can help make his new employers genuine title challengers, he could turn out to be the signing of the summer.

Blind is not answer to United centre-back problem

Daley Blind had a torrid afternoon as he was bullied by Graziano Pelle, who has begun this season as impressively as he started the last. The striker was left unmarked to collect David de Gea’s fine save from Sadio Mane’s volley to notch the opener. Minutes later, Pelle again rolled Blind all too easily to thump a low shot against the post. Blind is an impressively versatile footballer who is clearly able to adhere to the instructions of his demanding manager. The problem is that centre-back is probably the Dutchman’s third best position, behind left-back and midfield anchorman. He lacks the power, recovery pace and aerial ability to cope against the quickest and strongest front men. With Phil Jones expected back next week, Van Gaal needs to go with an all-English centre-back pairing and move Blind across to left-back.

Comeback kid: Rooney looked off the pace on his return to United team

Comeback kid: Rooney looked off the pace on his return to United team

Rooney is still labouring

As is so often the way with Wayne Rooney after missing a few games, he lacked sharpness on his comeback. Asked to drop deeper into his favourite No10 role to allow Martial to spearhead the attack, England’s record goalscorer delivered the fourth-most amount of passes of anyone on the pitch but there were few decisive ones. In comparision with the penetrative Martial, Rooney looked laboured and off  the pace. He did not have a shot and has now not scored in the Premier League since 4 April, or scored an away goal in the league since last November.