Canadian teenager Bianca Andreescu last night saw off the challenge of history-chasing Serena Williams to win her first major title in New York.

The 19-year-old battled to a 6-3, 7-5 victory in an entertaining final at the US Open in Flushing Meadows.

Andreescu's Romanian parents Nicu and Maria emigrated to Canada in the 1990s, and the young star has had a remarkable 12 months. She has now won 14 straight matches and an extraordinary 45 of her 49 matches this season.

This was also her seventh win over top-10 opposition this year, with 23-time Grand Slam champion Williams chasing her own bit of history heading into last night's final.

The 37-year-old Williams is just one Grand Slam short of equalling the record held by Margaret Court, and had excelled throughout the tournament in New York in the build-up.

With the victory, Ontario native Andreescu becomes the first Canadian woman to win a Slam singles title in the Open era. She said after the match that she had been feeling nervous in the build-up.

"I was feeling many, many things before the match, more than any other match. In the finals, playing Serena. I just tried to breathe as much as I could from the moment I woke up until the match.

"I tried to just do that throughout the whole match, to just keep my nerves in place. It wasn't easy at all, but I think that's what I've been doing really well throughout this whole year."

The moment has arrived!

Bianca Andreescu wins the first Grand Slam title of her career, defeating Serena Williams 6-3, 7-5.#USOpen | #WomenWorthWatching pic.twitter.com/slAVtj5QWz

— US Open Tennis (@usopen) September 7, 2019

Williams saved a championship point in the second set - a moment met with rapturous applause and noise around Arthur Ashe Stadium. Andreescu says she had to try to cope with that noise in her own way.

"I had some doubts because I've witnessed her come back from being 5-0 down, 5-1 down, 5-2 down. I just told myself to stick with my tactics. She started playing much better. I think the crowd really helped her, as well," the Canadian said.

"I was blocking out the noise, or trying to. I could barely hear myself think really. It was really, really loud. But I guess that's what makes this tournament so special... but it definitely wasn't easy, especially when she started coming back in the second set.

"I mean, it was expected. She's a champion. That's what champions do. She's done that many, many times throughout her career.

"I just tried to stay as composed as I could. It's hard to just block everything out, but I think I did a pretty good job at that."

Serena Williams plays her women's final at the 2019 US Open at Billie Jean National Tennis Center in New York City, NY USA, on September, 7, 2019. Andreescu defeats Williams 6-3, 7-5 to win her first US Open and Grand Slam title. Photo by Corinne Dubreuil/ABACAPRESS.COM

It was Andreescu's first time in the main draw of the US Open, while she becomes the first teenager to win a Grand Slam singles title since Maria Sharapova at the US Open in 2006.

Williams meanwhile was in a reflective mood afterwards and felt she didn't properly show up when she needed to.

"I believe I could have played better. I believe I could have done more. I believe I could have just been more 'Serena' today. I honestly don't think Serena showed up. I have to kind of figure out how to get her to show up in Grand Slam finals."

"I guess I've got to keep going if I want to be a professional tennis player. And I've just got to just keep fighting through it."