WTA icon Venus Williams is not ready to hang up her racket, jokingly branded herself a "professional rehabber" as she battles injury concerns during the twilight of her career.

The former World No.1 pulled off another upset on Monday at the Cincinnati Open, defeating World No.16 Veronika Kudermetova in straight sets to advance to the second round.

"I always joke that I'm a professional rehabber, not a professional athlete," said Williams after the match. "I needed a break from rehab. So I took a couple of months off (after her injury in New Zealand earlier this year).

"I was in France and I had a driver and I passed by the French Open. I was like, man, that looks fun. I was in Paris, and I tried to find a racquet. Serena has a place there so I found her shoes and racquet and then I felt ready to do it again.

"So right after Wimbledon, I went straight back to rehab. I felt like Amy Winehouse... I don't want to go!"

The 43-year old will play at the upcoming US Open later this month, where she is a two-time champion after winning in 2000 and 2001 - beating her younger sister in the latter year.