Tennis glamour girl Daniela Hantuchova thinks she is too skinny and weak and may have to sacrifice her pin-up status to succeed at the highest level.

The lightly-framed Slovakian is beginning to rival Anna Kournikova as one of the sport's most recognisable faces, but believes that may be stopping her reaching her full potential.

The teenager, who has risen to eighth position in the world rankings, thinks she needs to start bulking up if she wants to go any higher.

"Right now, it's all about power," Hantuchova said after losing 6-4, 6-3 to Venus Williams in the Australian Open quarter-finals on Tuesday.

"I think my tennis is there but sometimes they just hit it so hard I can't do anything about it."

Hantuchova, 19, won her first senior tournament in Indian Wells last year and reached the quarter-finals at the last three grand slams, only to lose to Venus or Serena Williams on each occasion.

At 1.81 metres, Hantuchova is taller than Serena and slightly shorter than Venus but is lighter than both at just 56 kilograms.

Like former world number one Martina Hingis, Hantuchova's skills and court craft are the equal of any player in the game but she lacks the muscle and power of her bigger opponents.

"The Williams sisters are the only ones that I have lost to in grand slams in the past year," she said.

"I'm doing weights now but I have to improve the speed of my service. I've got become faster and use those chances that I had today."

Hantuchova said the only reason Venus beat her on Tuesday was her superior serve.

The world number two thumped down six aces, including one at 201 km/h, the fastest by a woman since 2001 and 12 km/h quicker than Andre Agassi's best effort in his quarter-final win over Sebastien Grosjean.

"Venus came out and played unbelievable but I think that's what she needed to beat me," Hantuchova said.

"I had my chances today but she was just better. Her serve was incredible.

"When someone serves 201 km/h there's not much you can do about it. Anytime I felt like I was going to break her or something, she just served unbelievable.

"I think that made the difference, that my serve was not as hard as hers and she was getting some easy points on hers.

"This match has really shown me I have to work even harder on it.

"She's so big, she's got so much power but I don't see any reasons why I can't do that. I was glad that even though she served hard at some stages, I was able to get the return back."