Rafael netted a superb opener.
"I said to him he must have closed his eyes," Ferguson said with a smile when asked about Rafael's goal.
"He has three goals for us this season. The lad has had an absolutely magnificent season and is maturing all the time. He has had a fantastic game."
Ferguson was also quick to praise fellow goalscorer Ryan Giggs for another fine performance at Loftus Road, where he scored an iconic goal 19 years ago.
"He scored a great goal at that end actually all those years ago," he said.
"He scored at that end in a game we beat them 4-1, I think. Paul Ince scored an overhead kick so he has got a good record here."