By North-west correspondent Alex Stevens

Manchester United have stepped up their pursuit of Benfica sensation Renato Sanches by sending a delegation to scout him on Saturday night, Football Insider sources understand.

United will assess the 18-year-old midfielder in Benfica’s top-of-the-table trip to Portugese rivals Sporting Lisbon.

A source has told Football Insider that United are compiling a dossier on Sanches that includes how he performs in more testing conditions against leading opposition and away from home.

The 18-year-old midfielder has burst onto the scene this season, delivering a number of impressive performances for Benfica.

Portuguese daily Record report 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.

The fee has not been agreed as United work on negotiating a less expensive transfer fee for the teenager, who signed a new five-and-a-half-year contract in December that ties him to Benfica until 2021.

Manchester United chief Ed Woodward is in charge of transfers and contracts

Target man: Ed Woodward is in charge of negotiating deals at United

Super-agent Mendes, whose clients include Cristiano Ronaldo and Jose Mourinho, told Portugese newspaper O Jogo last month that United tabled a £30.8million bid in January for Sanches, who has been dubbed the ‘next Ronaldinho’.

Sanches currently has a £60.9m release clause in his contract, but it’s likely that United will be able to do business for less than that come the summer.

The teenager has established a solid reputation in Portugal, hitting two goals in his 16 league matches this season and also appearing in three Champions League fixtures.

He was an unused substitute as Benfica defeated Uniao Madeira 2-0 on Monday night.