New York -Top-ranked Serena Williams can reach the brink of two of the greatest achievements in tennis history Thursday by defeating Italy's Roberta Vinci and advancing to Saturday's US Open final.
The 33-year-old American, who already holds all four major titles, is chasing the first calendar Grand Slam since Steffi Graf in 1988 and trying to match Graf's Open Era career record of 22 Slam singles titles, two shy of Margaret Court's all-time record.
"There's always another record. There's always another person to catch," Williams said.
"I never really thought I would be in this position where I would even be talking about records, talking about passing Steffi Graf or even mentioning Margaret Court.
"I just grew up trying to be the best that I could and do the best that I could. I worked really hard for everything, so to even be mentioned in that conversation is great."
If Williams gets past 43rd-ranked Vinci, who has lost all four of their career meetings without taking a set, she will make her bid for history against the winner of Thursday's other semi-final between Italy's 26th-ranked Flavia Pennetta and Romanian second seed Simona Halep.
Three-time defending champion Williams, who seeks an Open Era-record seventh US Open title, is 7-0 against Pennetta and 6-1 against Halep in their career rivalries.
Williams has played down the one-year feat, saying she had more pressure completing her second "Serena Slam" than a calendar Slam, but she admitted as she reached he last four "It is important to me."
Only five players have completed the calendar-year sweep of the Australian, US and French Opens and Wimbledon -- Americans Don Budge in 1938 and Maureen Connolly in 1953, Australians Rod Laver in 1962 and 1969 and Margaret Court in 1970 and Germany's Graf in 1988.
Vinci suffered her most recent loss to Williams at a Toronto quarter-final last month.
"I'm not going to underestimate her," said Williams. "She has played really well. She's not in the semifinals of a Grand Slam for no reason. She knows what to do and she knows what to play.
"I just think it was great that I just played her because I kind of know what to expect, and I'll be more ready for it this time."
Vinci, 32, has already enjoyed a measure of success by reaching her first Grand Slam semi-final, even if she is facing Williams.
"I have a lot of experience, but when you play against Serena, doesn't matter," Vinci said. "You have to play better than better than better."
Williams is 53-2 this season and a huge favorite over Vinci but Pennetta warned not to discount her compatriot.
"I think she has a chance," said Pennetta. "She has to go in the court and try her best. You just have to go on court and try everything."
Czech fifth seed Petra Kvitova, a two-time Wimbledon champion ousted by Pennetta in the quarter-finals, beat Williams on Madrid clay in May. She said she would be shocked if Williams did not win the title.
"She's more focused than she has before, and she's that kind of the player who is playing better every match," Kvitova said.
"If she is going to be in the final, I think she is going to put everything that she has inside and she is going to win it."
Pennetta has won three of four meetings with Halep, including a fourth-round affair at the 2013 US Open, but lost their most recent meeting this year at Miami.
"It looks like she's not that powerful but she is," Pennetta said.
"To make a winner to her you have to finish the point seven times. She's really consistent. She's always there. The ball always come back. It's going to be like marathon."
After losing to Williams in the Cincinnati final, Halep said she would be cheering for her to complete the calendar Slam, although she has qualified that stance a bit.
"I want Serena winning if I'm not in the final," Halep said. "If I will be in the final, of course I will fight for my chance."