“‘You know perfectly well what I’m talking about! said Hermione shrilly. ‘You spiked Ron’s juice with lucky potion at breakfast! Felix Felicis!’
‘No, I didn’t,’ said Harry, turning back to face them both.
”Yes you did, Harry, and that’s why everything went right, there were Slytherin players missing and Ron saved everything!’
‘I didn’t put it in!’ said Harry, grinning broadly. He slipped his hand inside his jacket pocket and drew out the tiny bottle that Hermione had seen in his hand that morning. It was full of golden potion and the cork was tightly sealed with wax. ‘I wanted Ron to think I’d done it, so I faked it when I knew you were looking.’ He looked at Ron. ‘You saved everything because you felt lucky. You did it all yourself.'”
J.K. Rowling “Harry Potter and the Half-Blood Prince”