Hello and welcome to LIVE coverage of top seed and defending champion, Serena Williams' US Open quarter final with Italian, Flavia Pennetta. The players are due on Ashe shortly.

GAME, SET AND MATCH! - WILLIAMS 6-3 6-2 PENNETTA. The world number one shows just why she is the best female player on the planet with a display full of immense precision and power. The American seals a 19th straight triumph at Flushing Meadows in an hour and three minutes, crashing down a huge first serve to claim the match to 30. She will now face Makarova in the last four.

BREAK! - WILLIAMS 6-3 5-2 PENNETTA. Serena secures the double break as she pounces upon a slow second serve to despatch it down the line and take the game to 30. She will now serve for the match. It's been a quite magnificent performance by the reigning champion.

WILLIAMS 6-3 4-2 PENNETTA. The Williams juggernaut powers on. Pennetta is like a rabbit in the headlights as the world number one fizzes winners past her for fun. A deep second serve forces the return error and Serena consolidates to 15.

BREAK! - WILLIAMS 6-3 3-2 PENNETTA. It's a break to love and it looks ominous for the Italian from here. The point of the game sees the pair trade blows before Serena chases a lob to her own baseline and hammers a stunning winner down the line on the turn.

WILLIAMS 6-3 2-2 PENNETTA. It's a love hold for the 17-time Grand Slam winner after she peppers her opponent with a range of big first serves. Very impressive. There was nothing Pennetta could do under such an onslaught.

WILLIAMS 6-3 1-2 PENNETTA. Flavia pounds down an ace for 30-15 but is then overwhelmed by a rasping return by Williams that literally knocks her off her feet. A stunning crosscourt pass gives the world number one another break opportunity but the Italian retaliates with some big serves, including a sixth ace of the clash, to seal a fine comeback success.

WILLIAMS 6-3 1-1 PENNETTA. The Italian moves within a whisker of a break with more outstanding returning to lead 15-40, but Williams won't let her wriggle free and follows up a rasping crosscourt winner with an ace. The American appears to be insisting on making hard work for herself but eventually comes good to level.

WILLIAMS 6-3 0-1 PENNETTA. A huge hold for the 11th seed. She's really taken the game to Serena but it's simply brought the best out of the world number one. At 30-40 Flav fights off what is becoming an alarmingly regular break point before a pair of aces help her stop the rot and avoid the loss of a seventh game on the run.

SET! - WILLIAMS 6-3 PENNETTA. Flavia rediscovers some of the return-form that got her off to flyer and senses a way back into the set at 15-40. But Serena extinguishes her hopes with some huge first serves and takes the opener in 29 minutes courtesy of six games in a row. A quite sensational response by the reigning champ after Pennetta had stunned a packed Arthur Ashe stadium with some swashbuckling tennis early on.

BREAK! - WILLIAMS 5-3 PENNETTA. It's five games in a row for the top seed who takes advantage of the Italian's inability to land a first serve to lead 15-40. An ace out of the blue gives Flav hope but she cannons an anxious shot too long in the following rally to drop another service game. This set has all-but gone for her now.

WILLIAMS 4-3 PENNETTA. Flav's start was like a red rag to a bull. It has merely served to anger Serena and she has raised her game quite considerably. A love hold, including a rocket of an ace, sees Pennetta offer little resistance.

BREAK! - WILLIAMS 3-3 PENNETTA. Williams continues her outstanding response by clocking up double break point courtesy of a quite ridiculous forehand that angles right into the corner. Pennetta roars back to force deuce but is blown away by another sizzling forehand before a poor choice of shot at the net leaves her wondering what happened to her clear advantage.

WILLIAMS 2-3 PENNETTA. The top seed is being made to play that extra shot and at 40-15 Pennetta gets one more back that Serena completely blows by volleying tamely into the net. A fierce rally ensues but it's the American who prevails as Flav can't quite get enough height on a crosscourt forehand. A first hold for Williams.

BREAK! - WILLIAMS 1-3 PENNETTA. The five-time US Open champion bites back by reeling off a couple of return winners to cruise to a triple break point. Pennetta rallies and saves two but then slams a forehand into the net to gift Serena a foothold in the match.

BREAK! - WILLIAMS 0-3 PENNETTA. What a rampant start from the 11th seed! The accuracy and venom on her returns is leaving Williams all over the show. Two more break points have the defending champion in complete disarray and she has no answer to it as she lashes a shot long to fall further behind.

WILLIAMS 0-2 PENNETTA. The world number one hits back from 15-30 down to pummel her opponent with some big-hitting strokes from the baseline. She snares a break back chance but Pennetta responds to force the error following a dominant rally. The Italian is willing to trade blows with the explosive American and again gets her reward with a hard-fought hold.

BREAK! - WILLIAMS 0-1 PENNETTA. A strong start from Pennetta reaps some early rewards as she clocks up break point at 30-40 following a flurry of outstanding returns and a perfect passing shot.She clearly means business and another deep return causes Serena all sorts of problems, leaving her to awkwardly stab into the net.

Williams will serve first.

The players have finally arrived on Ashe after the delay caused by Nishikori's five-set triumph over Wawrinka. Just moments away now.

Surprisingly, Williams is featuring in her first GS quarter of the year and claims to have a different perspective on things that have helped her in this tournament. She said: "I think I put a lot of pressure on myself to do well, particularly in the slams. I had a couple of nagging injuries that definitely didn’t help. Now I’m more relaxed. I feel like I don’t have to win any more."