Williams sisters and Nadal to light up New York

NEW YORK (Reuters) - The U.S. Open should really come alive on Wednesday when the Williams sisters clash in a blockbuster quarter-final and men's top seed Rafael Nadal bids for a semi-final place.

In a repeat of this year's Wimbledon final, seventh-seeded Venus takes on No. 4 Serena, their 11th meeting in a grand slam event and 17th overall.

The two former U.S. Open champions are tied at 5-5 in grand slams and 8-8 overall, so something has to give when they clash under the lights.

"It sucks," Serena said. "Even the semi-finals would have been better than the quarters, but at least one of us will make it to the semi-finals."

Both players have been in outstanding form on their way to the last eight with Venus losing just 15 games and Serena one fewer.

Venus is focusing solely on the match.

"That will be a huge milestone to get by her to win this championship," she said. "That's pretty much how I see it, as trying to win the tournament."

Russian sixth seed Dinara Safina takes on Italian 16th seed Flavia Pennetta for the right to play the victorious Williams.

World number one Nadal will round off the day's action when he plays American Mardy Fish in the quarter-finals, looking to reach the last four for the first time.

The Spaniard was pushed hard by another American Sam Querrey in the previous round and is expecting another tough match.

"He's a very good player," Nadal said.

"He played the final in New Haven last week. He played the final in Indian Wells too this year, so he's a dangerous player on hard courts. I have to play very well if I want to win."

British sixth seed Andy Murray faces Argentine 17th seed Juan Martin Del Potro in the day's other match with both men looking to reach their first grand slam semi-final.

(Editing by Ed Osmond)