Serena Williams sent out a warning that she is the one to beat again after marching into the US Open quarter-finals with a ruthless 6-2, 6-0 victory over 22nd seed Daniela Hantuchova.

The defending champion, chasing her third grand slam title of the year and the 12th of her career, destroyed Hantuchova with the perfect mix of consistency and aggression.

Any hopes Hantuchova may have had of a shock win were ended as Williams rattled off 10 consecutive games to race into the last eight.

The second seed said she hoped to maintain that level of consistency as she tries to equal Billie Jean King's mark of 12 grand slams.

She said: "I just want to stay focused and play well in my next match. Hopefully, I'll be able to continue this."

The American now faces Italy's Flavia Pennetta, the 10th seed, who saved six match points when beating Russia's Vera Zvonareva 3-6, 7-6, 6-0.

Williams insists she'll be taking nothing for granted and said: "I think everyone is playing so well. You can't underestimate anyone."