I just never give up. I fight to the end. You can't go out and say, 'I want a bag of never-say-die spirit.' It's not for sale. It has to be innate.

If you can keep playing tennis when somebody is shooting a gun down the street, that's concentration.

Growing up I wasn't the richest, but I had a rich family in spirit. Standing here with 19 championships is something I never thought would happen. I went on a court just with a ball and a racket and with a hope.

I'm definitely not at my best. Honestly, I'm under 50 percent. But I've won stuff under 50 percent before.

I just never give up. I fight to the end. You can't go out and say, 'I want a bag of never-say-die spirit.' It's not for sale. It has to be innate.

I decided I can't pay a person to rewind time, so I may as well get over it.

I love metaphors. I've never been on this train. ... If I'm standing on the middle of a track, I'm definitely going to get derailed. I have to make sure that I'm on the train and not in front of it.