When Venus Williams swung, the unwelcome sound of racket frame hitting ball filled the stadium, and her serve barely reached the net's bottom fringe.
For Williams, any embarrassment was brief. She won the next two points with elegant volleys, closed out the game with an ace and went on to beat Roberta Vinci 6-1, 6-4 Saturday at the Sony Ericsson Open.
Williams blamed her shanked shot on bad timing.
"It's complicated," she said with a smile. "Tennis is just tough."
Ask Andy Murray. The defending men's champion lost his opening match to American Mardy Fish, 6-4, 6-4.
The upset meant Rafael Nadal will overtake Murray for the No. 3 spot in the next rankings. With the win, Fish reached the third round at Key Biscayne for the first time since 2003.
Williams, a three-time champion, advanced to the fourth round. She's the hottest player on the women's tour - not necessarily because of the red corset she unveiled this week, but because she has won 12 consecutive matches.
Williams is also the only American who reached the final 32 in the women's draw. She and sister Serena are the lone U.S. women in the top 40.
"It's just definitely strange because of the unbelievable tradition we've had with tennis for Americans since the beginning," Williams said. "That's what makes it so odd. With Serena and me, the standard has been set pretty high. Hopefully there will be someone coming along soon with the tools and the traits, and who will build that in their game to get there."
Top-ranked Serena has been sidelined with a knee injury since winning the Australian Open in January. She has been working out this month with fitness guru Mackie Shilstone but withdrew from the tournament before the start.
Venus, seeded third, seeks to add to the family's collection of eight Key Biscayne titles. She won in 1998, 1999 and 2001.
The ranks of top U.S. males have also be thinning, which made Fish's win something of a watershed. Ranked 101st, he earned only the second win of his career over a player ranked in the top three.
Fish lost just six points on his first serve and hit 28 winners to only nine for Murray, who went 1-for-5 converting break-point chances.
Williams was in control from the start against Vinci. She lost only eight points on her first serve and broke four times, repeatedly slamming big returns off Vinci's weak second serve.
Williams also came to the net 16 times, where her 6-foot-1 frame always makes for an imposing presence.
"This year I've just been to the net a lot," she said. "I think it's the motif that will just continue."
Williams won titles last month at Dubai and Acapulco and is 16-1 this year, with the lone loss to Li Na in the quarterfinals at the Australian Open two months ago. Her matches since include three victories after losing the first set.
"I've come from down, up, around and over," she said. "Being on a winning streak helps my confidence every time."
Vinci, ranked 55th, fell to 0-12 against top-five players. Former No. 1 Ana Ivanovic's recent struggles continued with a loss to No. 6 Agnieszka Radwanska, 7-5, 7-5.
Advancing on the men's side were No. 5-seeded Robin Soderling and No. 10 Fernando Verdasco. Soderling beat Peter Luczak 7-6 (5), 6-0, and Verdasco eliminated Dudi Sela 6-1, 6-2.