Manchester United have been handed a massive boost in their pursuit of signing Real Madrid star Karim Benzema.

According to French publication Le10Sport, Real Madrid are willing to let the star striker leave the club in the summer transfer window as they look to replace him with Manchester City star Sergio Aguero.

Louis van Gaal's side have already started negotiations with Benzema's agent in bringing him to Old Trafford. As part of the deal, David De Gea - who has long been a target for Real - will move in the opposite direction.

Benzema is not an untouchable player at the club anymore. The 10-times European champions' president Florentino Perez is open to offload the French international, if potential suitors could make a bid for the striker.

Real's arch rivals Barcelona currently holds the best attacking lineup in the continent, which includes the likes of Lionel Messi, Neymar and Luis Suarez. Perez is looking to further bolster the Spanish capital club's attack.

Perez has already identified Aguero as the Galactico signing of this year's summer transfer window. Should he make a switch to the Santiago Bernabeu, the Argentine international will join Cristiano Ronaldo and Gareth Bale to lead the attacking division for the next season.

Aguero's potential move to Spain will force Real to push Benzema out of the club as he is likely to become the star player to be sold this year. In the last two years, the La Liga giants have let Mesut Ozil, Angel Di Maria and Xabi Alonso leave the club, despite their impressive performances during their time in Madrid.

City could struggle in retaining their star striker and with Real's firm interest in Aguero, it could trigger a transfer merry-go-round, which could see Benzema move to United. Manuel Pellegrini's side could end up helping United sign the Frenchman.

Van Gaal allowed Radamel Falcao return to AS Monaco after he completed a season-long loan spell at United. Benzema could replace the former Atletico Madrid and Porto star at Old Trafford.