Defending champion Serena Williams walloped Spain's Carla Suarez Navarro 6-0, 6-0 to race into the semifinals of the US Open on Tuesday.

Top seed Williams served up the dreaded "double-bagel" in a quick-fire 52 minutes to set up a clash with fifth seed Li Na.

"Honestly she's a great player," said Williams, blaming windy conditions for the Spaniard's plight on her 25th birthday.