Manchester United need four signings in order to get close to champions Chelsea next season, according to former defender Gary Neville.

Memphis Depay has been confirmed as the club's first signing ahead of next term, but the 20-time English champions are set to finish well adrift of the title winners.

Victory over Crystal Palace all-but secured a return to the Champions League after a season away from Europe's premier club competition after an uncertain campaign for United which has been riddled with injuries.

The high-profile summer additions of Angel Di Maria and Radamel Falcao have also failed to pay off while captain Wayne Rooney has often been played out of position during Louis van Gaal's maiden campaign at Old Trafford.

And with Chelsea, Arsenal and Manchester City all threatening to pull away from United, Neville says some shrewd signings can help bridge the gap ahead of the 2015/16 season.

"What they have to do next season is challenge and get closer to the title," he told Sky Sports after the 2-1 win over Crystal Palace.

"For Louis van Gaal, this season is par. He has done exactly what he wanted if he completes the job in the next couple of weeks and gets into the Champions League.

"Having finished seventh last season, which was a terrible season, that's all that was asked of him this season. It looks like he's going to do it.

"They've already started buying the players. Depay has come in already so it looks like they're going to be aggressive and on the front foot in the transfer market again.

"It needs that really. If you look at Manchester United's squad at this moment in time it won't get close to Chelsea, as it currently is.

"But with three or four signings – the right ones – then they can challenge Chelsea for the title next season. Arsenal and Manchester City will feel the same.

"To win it in the third season probably would be his aim. To jump from here to win the title next season is probably what Louis van Gaal will be thinking, but it's a big jump."