Melbourne - Spain's Carla Suarez Navarro pulled off a major giant-killing act on Thursday with a stunning 2-6, 6-3, 7-5 upset of seven-time Grand Slam winner Venus Williams in the second round of the Australian Open.

The win, which included a 63-minute final set, marked the biggest career victory for the 20 year-old ranked 46th, whose total career prize money amounts to 348,000 dollars.

Multi-millionairess Williams, winner of 39 singles titles and 22 million dollars, served for victory in the third set leading 5-3.

But Suarez Navarro stayed calm in the face of danger, breaking the big-hitting American for 4-5 to continue a comeback from 2-5 down.

The Spaniard broke for a 6-5 lead and held her nerve to produce the win a game later.

The result leaves Williams, 28, with her second-worst showing in Melbourne after losing in the first round in 2006.

Suarez Navarro lost in the qualifying rounds in her first two Melbourne attempts and is playing in only her fourth Grand Slam.

"This is a very big court, " said the stunned youngster. "Today I'm very happy. I don't know how I won. I only played my game." (dpa)