Serena Williams battles to comeback win

(GETTY IMAGES)

Serena Williams has warned Wimbledon chiefs she deserves the same treatment as the top men after being kept off Centre Court and Court One again.

The defending women's champion, who has won four singles titles and a further four doubles titles at Wimbledon, was sent out to the distant Court Two for her second-round clash with Romanian Simona Halep, which she won in three sets.

So too was Williams' sister Venus, the five-time singles champion, for her opening match on Monday.

For Serena it meant venturing out of her comfort zone, and the 29-year-old believes she and Venus are getting a raw deal in comparison to the elite men.

"Yeah, they're never moved across," she said. "Venus and I have won more Wimbledons together than a lot of the players, or by ourselves in doubles even.

"They like to put us on Court Two, me and Venus, for whatever reason. I haven't figured it out yet. Maybe one day we'll figure it out. I don't know."

Serena complained last year when her second-round match against Anna Chakvetadze was put on Court Two on the day the Queen visited Wimbledon and watched the Centre Court action.

And now the younger Williams sister has indicated she will not necessarily take it in her stride if she is sent away from the two main show courts again.

"I don't necessarily think I should," Williams said. "I try to play my match and take that first and foremost, deal with whatever later.

"But obviously they're not going to change."

She added: "I don't make it a big issue. I think at some point maybe I should. I don't know.

"I just really try to focus on not going down on Court Two. At least now they have a review (system) out there, so I do like that.

"It was much better than the old one that was actually closer. I really hated that court."

At least Williams won, so she could half-joke that the walk out to Court Two, in the corner of the All England Club closest to Wimbledon Village, acted as "kind of a warm-up".

"It gets my legs moving," she said.

Her victory came after another scare, though, as she came from a set down to knock out 19-year-old Halep.

The American would have plummeted from 25th to 311th in the world rankings if she lost, relinquishing almost all the points she earned for her triumph in London last year.

When the opening set went to Halep, the four-time champion was in trouble.

But Williams had scraped her way past France's Aravane Rezai in a deciding set in the opening round, leading to a flood of tears, and had another comeback in store which allowed her to deny Halep and win 3-6 6-2 6-1.

If Williams was looking to be tested in the early rounds in preparation for the more accomplished opponents she would expect to meet in the second week, her wishes have been granted.

The more sets she plays the more she might look capable of winning a third successive Wimbledon title, which no female player has managed since Steffi Graf dominated from 1991 to 1993.

But Williams was not convincing today, and after her 49-week absence from the tour - caused by a foot injury and a blood clot - it would rank as perhaps her greatest achievement should she triumph in the final on Saturday week.

Williams has still lost just once before the third round at a grand slam, and that was as long ago as 1998 when she was defeated by sister Venus in round two at the Australian Open.

"I definitely feel like I started slow today," she said. "But I was actually really, really trying to start out fast. That obviously didn't happen but I also think that I got a little tight out there and I just need to relax."

By the third set she was playing well, but the slow change up to the higher gears in her performance might become a worry.

"I felt I was fine," Williams said. "I felt like, 'Okay, I just want to get it over with, just stay focused'."

She faces Maria Kirilenko next and presumably will be on Centre or Court One.

Williams knows it will be another difficult match.

"She just plays well. She moves well. She hits hard. Boy, she runs well," Williams said. "She does everything well. She's always looking to improve, so it will be a good match."