Martina Hingis won the Italian Open for the first time in Rome yesterday but not before American opponent Venus Williams had served warning she poses a real threat to the number one spot occupied by the Swiss.

Hingis may have avenged successive defeats to her fellow 17-year-old - in Sydney and Key Biscayne - but she was quick to admit that Williams is now her biggest rival on the women's tour.

"Right now, she's the number two player in the world," said Hingis, who had dropped just 15 games in four matches en route to the final but needed a 6-3 2-6 6-3 win to secure her 18th career title.

Despite losing in Rome, world number nine Williams has already won two tournaments this year and is expected to rise to number seven when the new rankings are announced today.

The Swiss player lost her famed concentration when the umpire overruled two questionable calls at 2-1 and, visibly irritated, lost the next eight points. But Hingis broke back immediately as she moved her opponent from one side of the court to the other, repeatedly forcing Venus into a series of unforced errors. From 23, Hingis reeled off four consecutive games to take a one set lead.