New York: Canadian Bianca Andreescu became the first teen US Open semi-finalist in a decade, rallying to defeat Belgium's Elise Mertens on Wednesday and advance to a last-four matchup with Belinda Bencic.
Andreescu, a 19-year-old from suburban Toronto, downed 25th seed Mertens 3-6, 6-2, 6-3 to book a Thursday clash against fellow Slam semi-final debutante Bencic, the Swiss 13th seed who beat Croatian 23rd seed Donna Vekic 7-6 (5), 6-3.
"I'm honestly speechless," Andreescu said. "I need someone to pinch me right now. Is this real life?"
Serena Williams, seeking her 24th Grand Slam singles title to match Margaret Court's all-time record, faces Ukraine's fifth-seeded Elina Svitolina in Thursday's other semi.
Either Bencic or Andreescu, who have never played each other, will reach her first Slam final on Saturday at Arthur Ashe Stadium, where first-time Slam winners have been crowned three of the past four years.
"Semi-final feels great right now," Bencic said. "I was dreaming about this day coming but you never know. I worked hard for this. Yeah, very nice feeling."
Andreescu, a winner this year at Indian Wells and Toronto, is the first teen in the US Open's last four since Caroline Wozniacki in 2009.
She credited being tested in her wins with giving her the poise to battle back after dropping the first set against a foe who had not dropped a set in the tournament.
"I think it's just the experience from playing these huge events this past year," she said. "All that experience is just catching up."
Andreescu could become the first teen to win a Grand Slam title since Maria Sharapova captured the 2006 US Open and she would be the youngest US Open champion since Russia's Svetlana Kuznetsova in 2004.
"This is honestly so crazy," said 15th seed Andreescu. "A year ago I was in the qualifying round. I remember I was suffering from a back injury."
Mertens had lost only 16 games in four matches, but Andreescu, her first seeded foe, hit 40 winners to 22 for Mertens.
Mertens broke for a 3-1 edge when Andreescu missed a backhand volley then held twice to claim the first set in 38 minutes.
"I was getting irritated because I wasn't playing my best tennis," said Andreescu.
Andreescu broke at love for a 4-2 lead and closed the second set by taking 16 of the last 20 points.
In the third, Andreescu smashed a backhand winner to break for a 5-3 lead and another on match point.
"I've been working a lot on my fitness and mental strength," said Andreescu. "It's a result of all the hard work I've been putting in."
BERRETTINI 1ST ITALIAN TO REACH SEMIS IN 42 YEARS
Matteo Berrettini became the first Italian man to reach the US Open semi-finals in 42 years Wednesday to set up a potential showdown with title favorite Rafael Nadal, who resumes his quest for a 19th Grand Slam crown.
Berrettini, the 24th seed, matched Corrado Barazzutti's run to the last four in 1977 after outlasting 13th-seeded Frenchman Gael Monfils 3-6, 6-3, 6-2, 3-6, 7-6 (5) in three hours and 57 minutes.
The 23-year-old from Rome will meet the winner of a later match between Spanish three-time US Open champion Nadal and Argentina's Diego Schwartzman for a place in Sunday's final at Flushing Meadows.
Berrettini joined Barazzutti, 1976 Roland Garros champion Adriano Panatta and Marco Cecchinato as just the fourth Italian to advance to a men's Grand Slam semi-final in singles.
"What a great fight. I think it was one of the best matches I maybe ever saw -- I was playing but I also saw. I'm really happy I don't know what to say," Berrettini said.
The first-time Slam quarter-finalist blew a 5-2 lead in the final set and four match points before finally seeing off Monfils in a thriller at Arthur Ashe Stadium.
"I was lucky I had match points and he didn't have it -- it's better when you have them. I'm really proud of myself, I was always focusing on the next point."
A nervous Berrettini doubled-faulted on his first match point at 5-3 before a resolute Monfils fought off two more on his serve to send the deciding set into a tie-break.
Monfils coughed up a costly pair of double faults in the breaker -- and 17 in total -- as Berrettini surged 5-2 ahead, the Frenchman rescuing a fourth match point before a booming serve from the Italian clinched a memorable win.
"Right now I don't remember any points, just the match point. I remember also my double fault I must be honest," Berrettini said.
Defeat for Monfils prolonged France's lengthy wait for a first men's Grand Slam title since Yannick Noah won the French Open in 1983.
"I know how to bounce back, I've had some tough ones here before," said Monfils, who was beaten by Roger Federer in the 2014 quarter-finals after holding two match points.
"It was tough, I was just competing as much as I could but there was a big lack of serving today."
"I'm going to take the positive from these two weeks," he added.