Cristiano Ronaldo told Portuguese media that his troublesome left knee was fine on Thursday during a training session in which a fan ran onto the field to get his autograph.
Ronaldo, who has suffered tendinosis around the knee, gave a thumbs up to RPT television when asked if he was 100 percent physically and said "it's fine."
Around 10 000 fans watched the open training session in Campinas in a carnival atmosphere.
At one point, a woman ran onto the pitch to try and reach Ronaldo, evaded one security guard and ran another 40 metres before being brought down by another.
Ronaldo, who played in Portugal's 5-1 friendly win over Ireland on Wednesday, went over to sign his autograph on her shirt before the Portugal players threw shirts into the crowd amid hysterical scenes.
Left back Fabio Coentrao was the only player to appear on the Portuguese federation's daily medical bulletin after he missed training because of a bruised right buttock.
Portugal face Germany in their opening World Cup game on Monday.
"Portugal will not change our style or identity against any opponents," said midfielder Joao Moutinho in a news conference after the practice. "We have to impose our type of football."