Serena back on top of the world

The 31-year-old American star clinched a 3-6, 6-3, 7-5 victory over Petra Kvitova in the quarterfinals of the Qatar Open to move back to the summit following a two-and-a-half year interval which almost saw her quit the sport.

"I am so sensitive nowadays -- I am always crying, but I never thought I would be here again you know," Williams told reporters.

"I have been through so much and I never thought I would be here," she repeated.

Williams first became World No.1 on July 8, 2002 at the age of 20 and will take top spot for the sixth time her career.

It is a remarkable comeback for Williams, who slipped as low as 175 in the rankings after missing almost a year with injury and a life threatening pulmonary embolism in 2011.

But she returned with a bang in 2012, winning Wimbledon, Olympic Gold, the U.S. Open and the WTA Championships, while she has also triumphed in 59 of her past 62 matches.

Williams, who will start her 124th career week at No.1 on Monday, beat Chris Evert's record of 27 years ago when she reached the top at the age of 30 and 11 months -- six months younger than her successor, CNN reported.

Serena Williams hits her own face

That's a total only bettered by Steffi Graf (377), Martina Navratilova (332), Evert (260), Martina Hingis (209) and Monica Seles (178).

The achievement had looked in doubt with Williams 4-1 down in the final set, but the American fought back to clinch a dramatic 7-5 victory.

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