Novak Djokovic and Caroline Wozniacki on Shanghai high

Wozniacki lived up to her billing as the new world No 1 when she withstood some fierce rallies to tame second-seeded Russian Vera Zvonareva 6-3, 3-6, 6-3 to claim the title 24 hours later than planned.

Djokovic took advantage of the 3-1 first set lead he had opened before torrential rain ended play on Sunday to win the title in the Chinese capital for the second successive year. "China is definitely a special place for me," the 23-year-old said as he received the gold China Open Cup. "This is definitely a confidence boost for me."

After smog blighted much of the tournament and rain forced it into an extra day, Djokovic looked keen to end proceedings quickly and catch his rescheduled flight to the Shanghai Masters.

The Beijing Olympics bronze medallist roared his way through the rest of the first set, breaking a jaded Ferrer twice. The eighth-seeded Spaniard staged a revival in the second set, sending the Serb scuttling across the baseline in vain to open a 4-2 lead, but any belief among the small crowd that a three-set thriller was in store was doused by Djokovic.

"I thought at 4-3 I had a chance and I then had one double fault," said Ferrer. "Maybe I lost my concentration a little and I couldn't come back to play well again."

Wozniacki also lost her focus in the second set as Zvonareva frustrated her with some thunderous hitting from the baseline but Denmark's new tennis queen soon pulled rank to leave the Russian flatfooted as she walked away with her sixth title of 2010.

"The whole match was just so close. I had advantages in all the first games in the first set but I just didn't take them," said Wozniacki. "I just stayed focused. I kept running and tried to keep the pressure on her to keep her moving."

As Wozniacki revels in her No 1 status, the previous onwer of that title Serena Williams said she might miss the rest of the 2010 season because her injured right foot hasn't healed properly. "I am likely out for the year now," Williams said in a posting on her official website. Williams said she "re-strained" her foot by overtraining. "In order not to make this worse, I have to chill on my physical workouts but I will immediately begin rehabbing as soon as I get the Doc's OK.Keep me in your prayers (I need them)," the posting said.

Williams' agent, Jill Smoller, confirmed the posting was from the 13-time Grand Slam champion and said she will be re-evaluated in the coming days.

If Williams is sidelined for the remainder of the season, it would be a blow to the WTA Championships in Doha later this month, as well as for the United States when they plays Italy in the Fed Cup final next month in San Diego. Last week, Williams' older sister Venus said she will miss the rest of the season because of an injured knee.