Scouts from Manchester United and Manchester City were posted at Vizela's clash with Porto on the weekend.
Porto won 2-0 thanks to goals from Mehdi Taremi and Eustquio.
United and City scouts were in attendance, reports O Jogo, though they weren't alone.
They were accompanied by Lyon, Lille, Rennes, Montpellier and Bordeaux (France), Getafe, Osasuna, Eibar, Valladolid and Santander (Spain), Fiorentina, Bologna, Atalanta and Verona (Italy).
The presence of Cerezo Osaka and Albirex Nigata, from Japan, and Sochi, from Russia, also raised eyebrows amongst Vizela officials.
