Madison Keys has admitted that earning the praise of Serena Williams has helped put a spring in her step ahead of the upcoming US Open.
The 20-year-old made it to the semi-final stage of the Australian Open earlier this year, before being edged out by Williams.
Rising American star Keys has made a big impression on the world number one, with Williams backing her compatriot to win a Grand Slam in the coming years.
Speaking to the Republican-American, Keys said: "That was a really nice thing for her to say, and it definitely makes me work a lot harder.
"If someone who is number one and has been number one for so long can say something like that about me, it makes me work hard and see if I can actually get there."
As well as reaching the last four of the Australian Open, Keys also made it to the latter stages of Wimbledon last month before being knocked out in the quarter-finals.
