NEW YORK — Canadian teenager Bianca Andreescu battled past a tenacious Taylor Townsend 6-1, 4-6, 6-2 in a late night thriller at the US Open on Monday to reach her first grand slam quarterfinal and end the American's fairytale run at Flushing Meadows.

Ranked 116th in the world and having clawed her way into the US Open main draw via qualifying, Townsend was the clear underdog against the 15th seeded Andreescu, who arrived at the year's final grand slam hyped as the next big thing in women's tennis.

"I have been working and dreaming of this for a long time," said Andreescu. "So it feels pretty dam good to be in the quarters.

"Every tournament I am in I expect to win but I know I have a lot of tough opponents before reaching the finals."

But Townsend, who had already knocked off Wimbledon champion Simona Halep in the second round, would not be intimidated even after being blown out in the opening set. The match was billed as a clash of styles with Townsend employing the serve-and-volley game that baffled the fourth seeded Halep going against the hard-hitting Canadian.

"She has a different game from many other people," said Andreescu. "It wasn't easy that's for sure.

"I don't normally play people like this but I made sure to work on my passing shots yesterday and I think it worked in the first and third sets.

"I'm glad I kept my cool in the end."

But Andreescu has shown in winning hardcourt titles in Indian Wells and Toronto that she is much more than a big serve and ferocious forehand.

The teenager comes armed with an improving all court game and has shown a willingness and ability to come to net.

There were, however, a few glaring cracks in Andreescu's game, particularly her serve as she committed eight double faults, many at critical moments.

As expected Townsend came out on the attack but Andreescu was ready countering the serve-and-volley with razor sharp passing shots and clever lobs to race to a 4-0 lead.

In command, Andreescu's serving troubles suddenly surfaced double faulting to gift Townsend a break at 4-1.

Andreescu's serving woes followed her into the second set helping Townsend to an early break and a 3-0 lead with another double fault on set point handing the American a break to extend the match.

With a shaken Andreescu taking a washroom break Townsend skipped rope on court to keep loose to the amusement of the Arthur Ashe Stadium crowd squarely in her corner.

The support could not save Townsend as Andreescu opened the third set with a break and charged in front 5-1.

Townsend refused to go away quietly fighting off four match points to extend the contest before Andreescu served out the match.

Never before past the second round of any grand slam Andreescu has confidently navigated her way into the last eight where she will face Belgian 25th seed Elise Mertens, who blasted her way into the quarter-finals with a 6-1, 6-1 demolition of another American surprise package wildcard Kristie Ahn. — Reuters