United won 2-0 at QPR yesterday.
"We started OK but then right out of the blue the lad Rafael has hit one out of the clouds into the top corner," said Redknapp.
"He'll never score another goal like that as long as he lives.
"Of course United will win the league now. They are certainties.
"Ryan Giggs is a fantastic player. It just shows what you can do when you look after yourself."