The three women who stand between Serena and history

NEW YORK -- It was easy to understand why Serena Williams arrived at the US Open uninterested in relentlessly talking about becoming only the sixth player in tennis history to achieve a calendar-year sweep of the Grand Slam tournaments. History has proved it's the toughest feat to pull off in tennis, not just the only major bauble to elude Serena.

So far, Williams says, her way of dealing with it the past two weeks has been to avoid watching any Open matches on TV, or paying any attention to the media coverage and chatter about the history she's chasing. But you could finally feel Williams start to look ahead just a little after getting past her sister, Venus, on Tuesday to advance to Thursday evening's semifinal round, along with Roberta Vinci and Flavia Pennetta of Italy, and Simona Halep of Romania.

While profusely complimenting how well Venus played, Serena praised herself as well.

Her confidence that she might just pull this off finally appears to be leaking out. The finish line seems so near.

"[This] was probably the toughest match I've played in a really, really, really long time where I wasn't beating myself," Serena said after defeating Venus 6-2, 1-6, 6-3.

"I think against any other player, she for sure would have won."

The unseeded Vinci -- who Williams plays next -- is given the worst odds of beating Williams among the three players remaining in the women's draw.

There was no avoiding that topic for Williams when an Italian reporter asked her directly about Vinci, saying: "Even in Italy, we think she has no chance. But what is your opinion?"

Williams didn't bother to disagree -- another indication she can feel her game coming together well enough to win her fourth straight Open title, finish off the Slam sweep and move into a tie with Steffi Graf at 22 major titles, second only to Margaret Court (24) in tennis history.

"She played me really tough, and I didn't really expect that," Williams said of Vinci, referring to their most recent match, a 6-4, 6-3 Williams win at the Rogers Cup in Toronto. "So I'm not going to underestimate her. I kind of know what to expect, and I'll be more ready for it this time."

Here's a closer look at the three women who stand between Williams and tennis history:

Roberta Vinci

There are many reasons why Vinci, who began this tournament ranked 43rd in the world, is given long odds of upsetting Williams. But this might be the best one: Even the 5-foot-5, 128-pound Vinci looked ahead to Thursday's match and joked about wearing a helmet to protect herself from Serena's booming groundstrokes and serve. "She's the favorite -- maybe she'll feel the pressure," Vinci said. "It all depends on her."

Vinci is 32, but this is her very first career Grand Slam semifinal in 44 majors played, so she's in uncharted territory and can't approach Serena's power. In fact, Vinci's own game is an anachronism. She's one of a handful of players left in women's tennis who still plays a one-handed backhand. She also relies on a slice -- a shot that doesn't figure to conjure up much fear in Williams.

Given all that, it would be nice if Vinci considered herself among the game's best service returners -- since Serena's serve is considered the best in the history of the game. But Vinci also concedes: "If she serves well, it's tough to return."

Pennetta, Vinci's countrywoman, was asked how Vinci could beat Williams, and Pennetta shrugged and allowed it will be hard. "She has to believe she can," Pennetta answered, "because if you go on the court and you are not that sure, or you are thinking, 'OK, it's done. I'm [satisfied with the semifinals],' it's going to be bad."

Record vs. Serena: 0-4

Simona Halep

Against former world No. 1 Victoria Azarenka on Wednesday, the Romanian star showed why most people gave the winner of their match the best chance of toppling Williams at Flushing Meadows.

Halep has a terrific quiver of shots. She's ranked No. 2 in the world. Though she's playing with a wrap on her right thigh, her coach Darren Cahill has insisted she's 100 percent. Pennetta says Halep's ability to run the court and her combativeness make her tough to beat.

"You have to finish a point seven times against her -- the ball just keeps coming back," Pennetta said.

Halep is also just 23, and she's been frank about attributing her second-round loss at the French Open and first-round defeat at Wimbledon to nerves and pressure she felt because of her newfound high world ranking. But the way Halep finished off Azarenka on Wednesday -- one of the toughest fighters and hardest hitters on the tour -- was impressive. Halep dictated play and took the first set. After Azarenka stormed back to take the second set and get an early break against Halep in the third, Halep pushed back and broke Azarenka again at 5-3. She coolly teed up a forehand and lashed a winner to set up match point, then won a brief rally that ended with Azarenka pushing a forehand wide, sealing Halep's impressive 6-3, 4-6, 6-4 win.

The concerns for Halep? She can be broken often on serve, and that can be more fatal against Williams than anybody. And Halep admitted after beating Azarenka that she was lucky a brief rain shower forced a stoppage in play four games into the final set, because she was tired.

"Thank God for the rain," Halep said.

Then, knowing the quick turnaround she faces versus Pennetta on Thursday, Halep added, "But I can be strong one more day."

Record vs. Serena: 1-6

Flavia Pennetta

Like Vinci, Pennetta -- the 26th seed in the Open draw -- was not expected to last this long in the tournament. Unlike Vinci, she's more of a threat to Williams because of the resourceful game she plays.

Pennetta, now 33, is the same age as Serena and not the sort of player who is easily flustered. She's good at following a game plan and thinking her way through matches. She has one of the more effective backhands on the women's tour. She's also good at covering the court.

Like most players, Pennetta can't match Williams' power. Few women on tour can. But Australia's Sam Stosur, who's no slouch in the power department, either, described why Pennetta is nonetheless tough to play, after the Italian beat her in the round of 16.

"The spin that I use and the weapons that I like to do against pretty much every single player doesn't seem to bother her," Stosur said. "She can let the spin come out of the ball. [It] almost looks like she's got lots of time to hit what she wants to hit. She serves very well against me. My big weapons don't seem to be weapons against her, so that makes life pretty tough."

Long story short: If Williams beats Pennetta, it's more likely to be because Williams is the better player, not because Pennetta was quaking in her sneakers or just happy to unexpectedly be a match from the final.

She has to get past Halep first. And that match figures to be a marathon. But Pennetta feels she's peaking at the right time. She rated her match against Stosur the best she's played all year.

In what way?

"Everything," Pennetta said with a smile. "Everything was really good: my serve, my return. ... I played really consistently from the beginning till the last point."

Pennetta also knows that Serena, like Azarenka, is one of those players "you have to push all the time. Because if you give her time to push you, you're gonna die on the court."

Record vs. Serena: 0-7