Happy Birthday Angelique Kerber: 10 quotes by the German tennis star

"Believe in yourself and all that you are. Know that there is something inside you that is greater than any obstacle."

"In tennis, it is not the opponent you fear, it is the failure itself, knowing how near you were but just out of reach."

"You have to fight through the tough days to earn the best days of your life."

"It's not always about winning; it's about putting up a good fight."

"Success is no accident. It's hard work, perseverance, learning, studying, sacrifice, and most of all, love of what you are doing."

"On the court, I've always been told that I'm too nice, that I smile too much. But, really, I don't want to change that. I am who I am."

"You never lose; either you win or you learn."

"The most important thing is to stay positive no matter what, to be yourself, and to never give up."

"Every match is a new experience. Every point, every game, every set is a new experience."

"In tennis, it's not the size of the dog in the fight, but the size of the fight in the dog."