Manchester United coach Phil Neville says the club will continue to invest in the first team squad in the January transfer window to avoid their rivals stealing a march on them in the race for the Premier League title.

United trail Arsenal by five points in the Premier League following a summer during which they made just one significant signing in the form of Marouane Fellaini from Everton.

Having missed out on a host of players including Ander Herrera and Gareth Bale, United boss David Moyes is expected to enter the market for additional resources in the New Year.

And Neville, a former United player who was appointed to Moyes's backroom team after leaving Everton last season, says the club must invest to avoid losing ground on their rivals.

"We have a fantastic squad as it is," he told the BBC. "In the transfer window early on in the season we were looking for players, that was well documented.

"That search continues. We need to keep reinvesting in the squad because if you stand still in this league you get left behind, as Manchester City found out last season when they didn't strengthen as much and they ended up losing the league [title]."

Amid a difficult start to the campaign Wayne Rooney has been United's outstanding performer of the season, scoring seven goals and making five assists in all competitions.

Rooney's latest contribution came in the win over Arsenal during which he provided the cross for Robin van Persie's headed winner.

And the England striker's form hasn't gone unnoticed with Neville claiming Rooney has been 'a shining light' this term.

"His level of performance not just in games but in training has been first class," Neville said. And at the start of the season when we weren't in the best of form, he was a shining light.

"Now you are seeing everybody else to come into form, and with the partnership between him and Robin van Persie, if they continue at that rate in terms of goals, then we will be right up there.

"If you look at facts, when they play together, Manchester United win football games."