By European correspondent Gianluigi Carrozini

Manchester United have stepped up their pursuit of Benfica sensation Renato Sanches after being given the green light by Sir Alex Ferguson, according to a report.

The Premier League giants have made the 18-year-old midfielder one of their chief summer transfer targets.

As revealed by Football InsiderUnited have regularly scouted Sanches since he burst on to the scene in Portugal earlier this season.

The English club have been compiling a dossier on Sanches that includes how he performs in more testing conditions against leading opposition and away from home.

According to the website of transfer expert Gianluca Di Marzio, United are ready to pay £47million for the teen sensation this summer.

It is said that 20-times Premier League winners have intensely watched the player this season and the board, prompted by the input of former manager and current director Ferguson, have been convinced to push ahead with what would be a mammoth deal.

Portuguese daily Record have reported that there is already a verbal agreement between United and Benfica for Sanches to move to Old Trafford in the summer.

Benfica are said to be demanding an initial payment of £31.5million supplemented by £15.9million in add ons, in a deal worth a total £47.4million.

However, Di Marzio reports that United want to spread the cost of the transfer in instalments over a four-year period.

United are working on negotiating a deal for the Portugal international, who signed a new five-and-a-half-year contract in December that ties him to Benfica until 2021.

The teenager has established a solid reputation in Portugal, hitting two goals in his 22 league matches this season and also appearing in three Champions League fixtures.

In other Manchester United transfer news, the club are looking at two other principal summer targets.