Serena Williams (right) shakes hands with sister Venus after their US Open women's quarter-final match on Wednesday night. Serena won in straight sets. - AP

NEW YORK (AP):

SERENA WILLIAMS barely got the better of older sister Venus Williams in a US Open quarter-final that was fit for a final, coming back in each set to win 7-6 (6), 7-6 (7) on Wednesday night.

Serena trailed 5-3 in both sets. She faced set points in both, including eight in the second. But she advanced to the semi-finals at Flushing Meadows for the first time since 2002, the year she beat Venus in the final for her second US Open championship.

It was the siblings' 17th meeting as professionals and Serena leads 9-8. That includes 11 matches at Grand Slams where Serena leads 6-5.

She also has the edge in major championships, 8-7, and only she can add to that total this weekend. The fourth-seeded Serena will meet No. 6 Dinara Safina in the semi-finals.

Unfortunate

"It's really just unfortunate it had to be in the quarters," Serena said.

Safina overpowered No 16 seed Flavia Pennetta 6-2, 6-3.

No. 2 Jelena Jankovic will face No. 5 Elena Dementieva in today's other semi-final.

Venus had a bunch of chances to take control, but in the end, as both women's play reached a very high level, it was Serena who pulled through. In the second tiebreaker, Venus had four set points and Serena saved them all.

"I'm a very good closer," Venus said, "so today was, um - I've never had a match like this in my life, so I guess there's always a first."

Two months after Venus beat Serena in the Wimbledon final, the start of the latest all-Williams showdown was delayed by more than an hour because of two lengthy matches that preceded it on the tournament's main court, including a women's doubles match and No six Andy Murray's four-set victory over No. 17 Juan Martin del Potro in the men's quarter-finals.

Grand Slam

Murray reached his first Grand Slam semi-final by winning 7-6 (2), 7-6 (1), 4-6, 7-5 in a match that lasted nearly four hours.

Murray, who ended del Potro's 23-match winning streak, clinched a rise to No. 4 in the rankings, matching the highest spot ever for a British man since the rankings began in 1973. Neither he nor del Potro played particularly well - each made far more unforced errors than winners - but Murray's biggest complaint was when his request to have the overhead video boards shut off during points was denied.