Manchester United are reportedly tracking Portugal's top clubs as they begin planning their summer transfer activity.
Ole Gunnar Solskjaer's side have been linked with a number of top players in this window as they look to improve on their middling first half of the season, with Bruno Fernandes and Gedson Fernandes both believed to be targets.
According to Goal.com, it is the talents of those players and Atletico Madrid forward Joao Felix that has led them to send scouts to watch all the games played by Benfica, Porto and Sporting Lisbon.
United have a history of snapping up young talent from the Portuguese top-flight, most notably Cristiano Ronaldo in 2003 and Nani in 2007.
However, they have also had a few misses when scouting players from the league, with Bebe making just seven appearances with the club in the four years he was there after joining from Vitoria de Guimaraes.
