Serena Williams eased past Sara Errani 6-1, 6-2 in the semi-finals of the U.S. Open at Flushing Meadows.

The 30-year-old will face world number Victoria Azarenka, after she got the better of Maria Sharapova in a close three-setter 3-6, 6-2, 6-4.

Williams marched her way to her sixth final in New York, with Errani, who is having her best year as a singles player, having also reached the final at the French Open, left with no answers to the power of Williams.

"I definitely played better today," Williams said. "I played better than my other matches.

"And playing someone (like Errani), you have to go better... I was more consistent. I did make some errors, but I was more consistent than I felt I was in the past."

Errani was hoping for some luck as well as some erratic play from the American champion, but was easily overpowered by Williams. "I just try first set to be a bit more on the defense, to receive a bit more far away, and play her high balls and try to make that game -- then was not so good, so I changed and try to be a bit more aggressive," Errani said of her strategy in the game. "In any case, it was very difficult."

Williams praised Errani on a successful tournament, with the 30-year-old expecting the Italian to continue to improve. "She played really well," Williams said. "She's such a good hope for Italy.

"She's such a good fighter. I can see her improve so much. She played really well."

The 14-time Grand Slam champion has the edge against Azarenka; the American has got the better of the world number one in the semi-finals of both Wimbledon and the London Olympics and holds a career 9-1 record. "I don't have anything to lose," Williams added. "I feel like I'm going up against I personally think the most consistent and the best player this year, being Victoria Azarenka... it will be a good challenge for me."