Barcelona technical director Robert Fernandez missed his team's victory in Greece this week to scout Manchester United forward Anthony Martial, according to reports in Spain.
Mundo Deportivo claims the Barca chief flew to Portugal to watch the Frenchman in action against Benfica as he weighs up an approach.
Fernandez saw Martial come off the bench to play the final 14 minutes of the Champions League game, which United won 1-0.
He had previously watched Tottenham claim a draw at Real Madrid in the Bernabeu on Tuesday night.