Eastbourne, England, 14 June 2011 | AAP

Unseeded Venus Williams made a winning return to tennis after a five-month injury absence, surprising German eighth seed Andrea Petkovic 7-5 5-7 6-3 in a first-round upset at the Eastbourne grasscourt event on Monday.

Williams joins her sister in making a comeback to tennis, a week out from Wimbledon, with Serena out for almost a year due to foot surgery for a cut followed by a blood clot scare in her lungs.

The 13-time grand slam champion makes her start on Tuesday at Devonshire Park, facing Tsvetana Pironkova of Bulgaria.

Venus Williams had to quit in the Australian Open third round in January after one game against rising player Petkovic.

“It was very interesting when I drew her,” said Williams, whose last Eastbourne appearance was in 1998. “It was a tough match for her, because I’m kind of a floater right now.

“Normally, she would probably get through the first round. That was a little bit of bad luck for her but, for me, it was a great opportunity. It felt fitting in a way, very ironic – but a great way to start it all off.”

Williams annulled a break for her opponent in the first set as Petkovic led 4-2, going on to take the opener. The German claimed the second set, but could not hold off Williams in the third and the American won in two-and-a-half hours, as the sun finally came out after several days of rain and chill.

“I felt like I’m competing pretty well and just getting a feel for everything out there again,” said five-time Wimbledon winner Williams. “The conditions were pretty tough with the wind.

“I didn’t feel like I could be as aggressive with my serve as I wanted to be. Hopefully, maybe if the wind will die down, it will give me a chance to really get used to the courts.”