– Angelique Kerber

"Hey @AngeliqueKerber two is the double of one!!! #2slams... #1"

– Former Australian F1 driver Mark Webber

"Breathe Angie, breathe."

– Ex-British tour player Anne Keothavong, now a TV pundit.

"Congratulations @AngeliqueKerber on your @usopen championship & being the new #1 player in the world."

– Billie Jean King

"A year ago Kerber Baby was #11 in the world. Her name never came up as the one who could be the next to step up -- full credit to her determination."

– Brad Gilbert, former player and coach, now analyst for US television.

"What a week! What a year!"

– Fellow German player and former Wimbledon runner-up Sabine Lisicki.

"Congrats @AngeliqueKerber 4 your 1st @usopen title & n° #1 ranking @WTA,but so impressed by @KaPliskova."

–France's former Wimbledon champion Marion Bartoli.

"Congratulations to Angelique Kerber for 2nd major win this year and #1 ranking, well done to Plísková, a future major champion:)"

– Martina Navratilova