Robin van Persie and Louis van Gaal
Redknapp believes van Gaal needs to fill the gap left by van Persie.Getty

Former Tottenham and QPR manager Harry Redknapp believes Louis van Gaal is looking to continue his summer overhaul with the addition of a top-class striker in order to turn Manchester United's squad into serious title contenders.

The Dutch Boss has already spent around £80m ($125m) bolstering the other lines of his squad with the signing of Memphis Depay, Matteo Darmian, Bastian Schweinsteiger, Morgan Schneiderlin and have also signed goalkeeper Sergio Romero.

Van Gaal, however, is yet to sign a number nine despite the departure of both Robin van Persie and Radamel Falcao leaving him with Wayne Rooney and academy star James Wilson – and the future of Javier Hernandez Chicharito still up in the air – as his only options up front.

Redknapp believes that United have completed some excellent business so far during the summer but still understands that van Gaal will try to sign a top striker to complete the overhaul.

"If Manchester United signed a top-class striker then I think they'd be serious contenders for the title," Redknapp told Kicca.

"I watched their match against Barcelona last week and thought they played well. Wilson is very good but won't, I imagine, be able to carry them up front next season so I reckon Van Gaal will be looking for a top striker and, if he gets one, then they've got a real chance.

"He's made some excellent buys already this summer. Morgan Schneiderlin and Bastian Schweinsteiger will really strengthen the side and another striker will make them top contenders."

Meanwhile, the former Tottenham boss, has also backed van Gaal's decision to part ways with van Persie as he believes that, at his 31, the veteran striker's best moments are over.

"I imagine they let Robin van Persie go because his goals to games ratio was decreasing, that, along with his age and his past injuries, told them now was a good time to sell," said Redknapp.