Liverpool had scouts posted at Porto's clash with Famalicao.
O Jogo says the Reds were the only Premier League represented at the game yesterday.
Porto won 4-2 on the day.
Also in attendance were scouts from Ligue 1 Marseille, Nice, Saint-tienne and Strasbourg, as well as the Italians from Bologna and Frosinone, and the Swiss from Sion.