Harare — CARA Black and Liezel Huber meekly surrendered their US Open women's tennis doubles title when they lost to Americans Venus and Serena Williams in the final on Monday night.

According to reports from Flushing Meadows in New York, top seeds and co-world number ones Black of Zimbabwe and her American partner Huber were no match for the powerful Williams sisters who beat them in straight sets 6-2, 6-2.

In a very high quality match the two teams combined had 64 winners to just 25 unforced errors  Venus and Serena Williams, the number four seeds, took it to top seeds Black and Huber, breaking twice in the first set and two more times in the second set.

By contrast, the sisters did not face a single break point in the 89-minute match in winning their second Open doubles title, and third Grand Slam crown of the year after doubles triumphs at the Australian Open and Wimbledon.

They received a winner's prize of US$400 000 while Black and Huber will split US$200 000 for losing in Monday's final. Black and Huber played three three-set matches en route to Monday's final.

"We had great opponents today," said Venus. "Liezel and Cara, they played so well, survived so many close matches to get here. And they truly are the number one, day in and out on the tour."

The sisters won three of the year's four majors. They were playing the world's top-ranked team proof that rankings have more to do with playing lots of events, which the Williamses don't.

Black and Huber top the season rankings but struggle to outplay the Williams sisters in the year's major events. "They are bigger and stronger than us and they serve much better than us," Black said. "Although we're ranked number one, they are definitely stronger than us."

"They're bigger and stronger than us," Huber added after Monday's final. "They served bigger than us and you could see it all today." Serena was playing one day after being fined US$10 000 for an expletive-laced rant at a lineswoman, and another US$500 for racket abuse during her semi-final singles match against Kim Clijsters on Saturday.

She released a statement on Monday apologising for her tirade but declined to discuss the issue when addressing the crowd following the doubles victory. As for the tennis it was an easy victory.

Serena kept a noticeable sliver of green between her foot and the baseline whenever she served. She didn't get called for a foot fault. The sisters now have 10 major doubles titles, a tally that includes three Australian Opens (2001, 2003, 2009), one French Open (1999), four Wimbledons (2000, 2002, 2008, 2009) and now two US Opens (1999, 2009).

Black and Huber have been co-ranked number one since the year-end rankings in November 2007. They have four majors, namely Wimbledon in 2005, the Australian Open and Wimbledon in 2007 and the US Open last year.

Meanwhile, Black amassed a total of US$270 000 after reaching the finals of the women's doubles and mixed doubles at this year's US Open. Black first collected US$70 000, which she shared with Indian men's tennis ace Leander Paes after they lost in the final of the mixed doubles last Thursday.

She then went on to collect US$200 000 which she split with Huber after they lost in the women's doubles final to the Williams sisters on Monday. As an individual, Black collected US$135 000 after her two-week stay at Flushing Meadows in New York this year not bad for a 30-year-old who is reaching the twilight of her career.

Black has so far made a total of US$607 378 on the road this year. She has collected US$525 285 with Huber in the women's doubles and a further US$82 093 in the mixed doubles competitions.

Black collected the US$82 093 in the mixed doubles competitions which she played at all of the year's four Grand Slam tournaments -- the Australian Open, French Open, Wimbledon and the US Open.

In career prizemoney, Black has now made US$5 866 727 since she turned professional in January 1998.