The first match of the evening sees Venus (above) and Serena Williams meet for the 17th time with an 8-8 head-to-head record

Venus makes the early running but is broken by her sister Serena (above) when serving for the set at 5-3 and a tie-break follows

Two set points go begging for Venus in the tie-break and she can hardly believe when Serena comes through 8-6

Venus starts well in the second set and goes 5-2 up but again Serena digs deep and battles her way through to another tie-break

Venus lets slip four break points in the tie-break to make it 10 for the match, allowing Serena to prevail 7-6 (8-6) 6-6 (9-7)

British number one Andy Murray is playing in his first US Open quarter-final but sees an early break cancelled out by Argentina's Juan Martin del Potro

Del Potro rallies to find himself serving for the set at 5-4 up, but Murray is in aggressive mood and breaks back immediately

The first set is decided by a tie-break and it is Murray who holds his nerve to come through, Del Potro going down 7-2

Del Porto breaks to love when Murray serves for the second set at 6-5 up and now a second tie-break awaits

But the tie-break is another one-sided affair, Murray rampaging to a 5-0 lead before closing it out 7-1 and moving into a two-set lead

The third set sees breaks exchanged before Murray's game crumbles - Del Potro breaks for a 5-4 lead and then serves out

The players exchange breaks twice but Murray overpowers Del Potro at 6-5 up to win 7-6 (7-2) 7-6 (7-1) 4-6 7-5

After a tempestuous meeting in May, Murray and Del Potro embrace at the net to provide a fitting end to an outstanding quarter-final

Sixth seed Dinara Safina takes on Italy's Flavia Pennetta looking to reach her first US Open semi-final

Safina makes an impressive start as she breaks her Italian opponent twice to take the first set

Try as she might, Pennetta has no answer to Safina's power and variety and the French Open semi-finalist dominates the second set

A job well done for Safina, who cruises into the last four with a 6-2 6-3 victory on Arthur Ashe Stadium

American Mardy Fish provides an exciting climax to the day as he takes the first set from world number one Rafael Nadal

But Nadal slowly begins to reel Fish in at Flushing Meadows, romping through the second and third sets

Fish is broken in the third game of the fourth set and reacts by slamming his racquet to the floor in frustration

It's game over for Fish as Nadal seals victory at 2.10 local time to reach his first US Open semi-final