For the first time in two weeks in Flushing Meadows, the 19-year-old looked confused on the court. For a minute, Williams had all the momentum, and it seemed as if she wasn't going to look back.
It was a historic night on the tennis courts in NY for Canada.
Andreescu lost four games straight to allow Williams back on level terms at 5-5.
"It's so hard to explain in words but I'm just beyond grateful and truly blessed", Andreescu said on court.
Chances are, she'll do fine in the future.
Andreescu tied Monica Seles, who lifted the 1990 Roland Garros trophy in her fourth major, for the record as the fastest player to win her first Slam title in the Open era.
While there was a loud applause from the crowd when Andreescu was introduced before the match, the ovation for Williams was deafening.
"With her character and mindset, for sure she's going to win several Grand Slams", Mouratoglou said.
It wasn't a pretty match for Williams, who struggled on her serve throughout, with her first-serve percentage dipping to 25 at one point in the second set. "It was nice to see her win". And in a press conference following the match, Williams shared an incredibly vulnerable explanation for her surprising loss.More news: Bills vs. Jets Cheat Sheet: Odds, Picks, More
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Bianca Andreescu began her day Saturday the same way she started every morning during her run to the U.S. Open title. "It's such an honor for me and my opponent to play here". It's inexcusable to play at that level'. "I was just in awe of how loud the US Open crowd can get, it was insane but I was glad I witnessed that because that's what makes this tournament so special".
Andreescu talked about her meditative process throughout the U.S. Open, and said after her semifinal victory against Belinda Bencic that she had visualized winning the Grand Slam in NY, even writing herself a fake winner's cheque when she was 15.
"I'm really looking forward to what I can do in many years to come". "For it to become a reality is just so insane", she said.
"I've really strived to be like her", Andreescu said. I believe I could have just been more Serena today. "I really believed there were gonna be good times ahead because I think when you believe in that, all those tough times are worth it".
She has now been the runner-up at four of the seven majors she has entered since returning to the tour after having a baby two years ago. We need a better season than previous year.
And she's struggling to find answers for bad performances in the biggest matches.
"I've looked up to her and now actually winning the tournament, I've always thought I could but it actually happening is just so insane".
"She could have been a little bit intimidated for many reasons. Serena, the stadium, the world is watching". "She's an inspiration to many, many people", Andreescu said after beating the 23-time Grand Slam victor. As he posed for pictures with Andreescu, someone had to tell him to turn the trophy around because he had the wrong side facing forward.
Williams: "I don't understand that question".
"Well, get used to it", Andreescu responded.