Serena Williams
Serena Williams wins her fifth US Open title. [Reuters]

World number one Serena Williams won her fifth US Open title by defeating Victoria Azarenka in a hard fought final at Flushing Meadows on Sunday night.

The 31 year old was pushed to the limit in the first two sets before finally taking control of the match and claiming a 7-5 6-7 (6-8) 6-1 victory that saw her become a 17-time Grand Slam champion.

Before the final Azarenka had claimed that Williams should be recognised as the greatest player in history and the American duly delivered, moving within one slam of Martina Navratilova and Chris Evert.

Williams remains seven shy of Margaret Court's record total of 24, but by defeating Azarenka for the second year running in the US Open final she becomes the oldest women's winner of the tournament in the Open Era.

Despite racing to victory in the final set this was one of the toughest finals that Williams had played in, with Azarenka forcing the veteran American to dig deep and produce some wonderful tennis in testing conditions.

"Victoria played unbelievable, and what a great match," said Williams after claiming the title. "Vika's such a great fighter and that's why she's been able to win multiple grand slams, so it was never over until match point."

With a swirling wind on Arthur Ashe Stadium there were bound to be plenty of errors and the first two games of the match would see both players lose their serve.

Azarenka was able to deal better with the gusting wind in the early stages and moved 5-4 ahead with Williams serving to stay in the set.

Serena Williams
Victoria Azarenka congratulates Serena Williams after losing to the American for the second year running. [Reuters]

The Belarusian sensed an opportunity but despite seeing her opponent produce a double fault and a foot fault, she was unable to convert as Williams produced two stunning back hands and a timely ace.

The pressure was now on Azarenka and she failed to hold onto her serve as Williams hit an array of winners before confidently holding on to her serve to claim the first set in 58 minutes.

Williams then raced into a 4-1 lead in the second set before her 24 year old opponent would fight back to level it up at 6-6 and force a tie break.

The momentum was now with Azarenka and she forced a number of errors from Williams to take the final into a deciding set.

The first three games with go with serve as Williams took a 2-1 lead before the number two seed finally crumbled and was unable to win another game as she lost her second consecutive US Open final to the same opponent.

"It is a tough loss but to be in a final and to play against the best player who deserves to win today is incredible," said a clearly disappointed Azarenka. "We gave it everything we got, but it was well deserved and congratulations Serena."