Williams beat Li Na will face Azarenka for Cincinnati crown

World number one Serena Williams fought a hard battle and beat defending champion Li Na 7-5 7-5 to reach the final of the Western and Southern Open on Saturday and close in on one of the few titles that elude her.

The 31-year-old Serena can fill that hole in her resume on Sunday when she takes on Belarusian world number two Victoria Azarenka, who was a 4-6 6-2 6-3 winner over 2009 champion Jelena Jankovic of Serbia.

Williams, who has been critical of her performance in Cincinnati despite making it to the final for the first time, was not at her dominating best against Li but it was a good enough effort to put herself in line for a $1 million bonus.

Her appearance in Sunday's final combined with a win last week in Toronto has put Williams at the top of the U.S. Open Series bonus challenge and sends her to Flushing Meadows with a chance to compete for the largest payout ever awarded at the year's final grand slam.

Williams can pocket $3.6 million, with the million-dollar bonus supplementing the $2.6 million cheque for winning the women's singles at the U.S. Open.

In a career that has generated 54 singles titles including 16 grand slams, Williams has won just about everything there is to win in her sport but Cincinnati, one of the WTA Tour's most prestigious tournaments, is not among them.

Li stepped onto centre court well-rested having received a walkover into the semi-finals when Poland's Agnieszka Radwanska withdrew from the tournament to attend her grandfather's funeral.

But the 31-year-old fifth ranked Chinese got off to a sluggish start as Williams recorded the early break to move ahead 4-1.

Li hit back, sweeping through the next four games to pull in front 5-4, but Williams upped her game when needed, breaking her Chinese opponent twice more to take the set.

Williams and Li held serve to open the second but the set would soon dissolve into series of breaks.

In the end, Williams claimed the decisive one when Li double-faulted.

While Williams and Li may have struggled with their serves, their problems were minor compared to Azarenka and Jankovic, who managed to hold serve a grand total of just four times over three ugly sets.

Of the 27 games played, 23 ended in breaks, with the miserable serving display marred by 20 double-faults, 11 by Azarenka and nine from Jankovic.