Drama built at Arthur Ashe Stadium around the upcoming match, postponed from Thursday by rain, between three-time defending champion Williams and Italy’s 43rd-ranked Roberta Vinci, in her first Grand Slam semi-final.
Williams, on a 33-match Grand Slam win streak and a 26-match US Open win streak, is only two victories shy of completing two of the most incredible achievements in the history of tennis, playing her best tennis at an age once thought impossible for such success.
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.
Williams, who is 4-0 lifetime against Vinci, owns a 7-0 career edge on 26th-ranked Pennetta, who took just 59 minutes to dispatch second-ranked Halep 6-1, 6-3 and reach her first Grand Slam final.
“It’s amazing,” Pennetta said. “I didn’t think to be so far in the tournament. I played really well. I don’t know how to handle all the inspiration I have.
“Really nothing changed. I tried to play every match the best I can from the first one, don’t worry about the draw and focus on the things I have to do on the court. And here I am.”
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 Court in 1970 and Germany’s Graf in 1988.
Williams, 53-2 this season, seeks her 70th career title. She is trying for a seventh US Open singles crown, an Open Era record and one shy of Molla Bjurstedt Mallory’s all-time record, and a fourth US Open trophy in a row, matching Chris Evert for the Open Era mark.
Also within Williams’s reach is stretching her own mark as the oldest Open Era Grand Slam champion, set when she won Wimbledon last July to complete the “Serena Slam” of four Slam titles in a row, and boosting the longest gap between first and latest Slam titles in history to 16 years.
In a span that began with the 1999 US Open crown at age 17, Williams has won three French Open titles and six Wimbledon, Australian Open and US Open crowns.
Williams is 21-4 in Grand Slam finals and could be going for her ninth Slam final victory in a row, last losing one at the 2011 US Open to Samantha Stosur. She has won her past 15 finals overall, last losing at Cincinnati in 2013.
Pennetta, 33, broke Halep in the fourth game and again in the sixth when the Romanian netted a forehand on the way to taking the first set in 28 minutes.
Pennetta and Halep traded breaks to open the second set and again in the fourth and fifth games of the second set.
Halep led 3-1 but double faulted to surrender a break and Pennetta held and broke twice more for the victory, a forehand winner capping her fourth win in five tries over Halep.
Pennetta becomes only the third Italian woman in a Slam final after Francesca Schiavone won the 2010 French Open final and lost in 2011 and Sara Errani, who lost the 2012 French Open final.
If she hoists the trophy in her 49th Slam appearance, Pennetta would have the most tries of any Grand Slam women’s champion, two more than France’s Marion Bartoli when she won at Wimbledon in 2013.