Williams cruises through

The American, who sent an ominous warning to her rivals on Monday with a 'double bagel' win over Andrea Hlavackova.

And she hardly gave the 12th-seeded Serbian a look-in on Arthur Ashe Stadium as she powered to a 6-1 6-3 triumph in just 58 minutes.

Williams, 30, is the favourite to win a fourth US Open crown after her stellar summer that brought victory at Wimbledon and two Olympic gold medals.

Authority

And she wasted no time in asserting her authority over former world number one Ivanovic, racing into a 3-0 lead before the 24-year-old got a game on the board.

That came courtesy only of a fortuitous half-volley, but proved only temporary respite as 14-time grand slam singles winner Williams cruised through the remainder of the set - clinching it in just 25 minutes.

An early break for Williams in the second set saw the match continue in the same vein as Ivanovic, contesting her first major quarter-final since her 2008 French Open triumph, struggled to contain the three-time former champion.

Another break swiftly followed as Williams, runner-up to Australia's Sam Stosur at last year's tournament, completed another impressive win.

"I think I came out really strong," Williams said in a courtside interview.

"Playing against someone like Ana, a former world number one, you really have to play amazing tennis."

The fourth seed will face Italy's Sara Errani in the last four, the 10th seed having earlier continued her remarkable season by beating best friend and doubles partner Roberta Vinci 6-2 6-4.