The Real Madrid coach travelled to Germany on Saturday to have a closer look at the young midfielder, who is being heavily linked with a move to Europe
Sao Paulo president Juvenal Juvencio revealed last week that his Madrid counterpart Florentino Perez has contacted him about the 19-year-old, and Mourinho opted to visited Saturday's match in Germany to see the midfielder in action himself.
Mourinho's spokesman Eladio Parames has revealed via Twittter that the Madrid boss was in the stands for the friendly but refused to comment on whether the Portuguese boss was at the game specifically for Lucas.
The youngster featured from the starting whistle in Brazil's 3-1 victory, before making way for Giuliano in the 82nd minute.
Sao Paulo recently turned down offers from Chelsea and Inter for the teenager, who has a contract with his current club until December 2015.