NEW YORK, NY, USA - The killer instinct so critical for Bianca Andreescu’s world beating game has always been there, according to her coach Sylvain Bruneau, but the 19-year-old’s biggest challenge will be how to continue to channel and direct that energy in every match.

Speaking at his WTA Coaches press conference ahead of the No.15 seed’s US Open quarterfinal clash, coach Bruneau reflected on his teenage charge’s incredible, head-turning rise up the rankings and the source of her competitive drive - as well as revealed the ‘fun’ challenges involved in coaching a young, raw talent like Andreescu. 

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“I always thought she was going to be a really good player. For me, that was a given,” Bruneau told journalists on Tuesday.

“But that she was going to be able to get that quick of a turnaround from a year ago - she lost qualies here [at the US Open] first round, and then a year later…” He trailed off, struggling to sum up his pupil’s incredible rise. “No. That was faster than expected, definitely.”

Competing in her first US Open main draw and playing her first matches on the cavernous Arthur Ashe Stadium are just some of the latest ‘career-first’ milestones for Andreescu in a year full of them - experiences that Bruneau must prepare her for as best as he can. 

“You try to give them a heads up about what could be and what could not be, and how you want to look at things and how you want to handle it,” Bruneau explained. “But I think that you need to put both feet in the water and get your feet wet and just go through it to really see what it’s like. 

“I think the discussions are good, and they’re probably a little bit helpful. But there’s nothing like going through it. And she did it, so good on her.” 

He added, “I think that she’s done really good so far just managing all of it.”  

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Having previously worked for Tennis Canada for 30 years, Bruneau said Andreescu caught his eye early on with her fearless Fed Cup performances. In 2017, Andreescu dropped just 14 games as Canada took on Venezuela, Bolivia, Paraguay and Chile in Zonal ties, and was instrumental in getting the team back into World Group II by the end of the same year. 

Bianca Andreescu's coach Sylvain Bruneau speaks to press at his WTA Coaches press conference. (Jimmie48 Photography/WTA)

“I was always struck by how she was not afraid of opponents, or not intimidated by situations that I felt, at first, when she was 15, 16, could be intimidating,” Bruneau told press. “And she wasn’t. 

“I was always a little bit surprised initially, because I was getting to ‘discover’ her and getting to know her then. I was a little bit surprised at how she would just take everything, and I noticed very early on that she was a born competitor.

“I mean, she’s always been a little bit like this, I think it just needed to be channeled and help her get some tips on how to use all this energy.”

Bruneau and Andreescu began their coaching partnership in March 2018. Back then, the teenager was gearing up to play a string of ITF 25K events in Japan, and her ranking was hovering around the edges of the WTA’s Top 200. The pair resolved to study the players competing at the adjacent men’s events, note the differences between them and the women’s players, and figure out what to incorporate from both into Andreescu’s already ‘complete’ game. 

“I feel that her game, actually, is fairly complete,” Bruneau assessed. “I mean, there’s a lot of room for improvement still, obviously she’s still 19. But her game is very complete. 

“She’s able to do a bunch of different things on the court - which sometimes is great, which sometimes gets her in trouble, but overall has been good.”

Andreescu chats with coach Bruneau at a US Open practice session. (Jimmie 48 Photography/WTA)

That same signature variety and power that makes Andreescu’s matches so exciting for fans to watch also presents an interesting challenge for Bruneau as a coach. Andreescu admittedly struggles to keep stimulated with repetitive drills, which prompts Bruneau to always try to keep the practices creative, working on different strokes and combinations instead of the same routines over and over again. 

“It’s a lot of fun because then you work with a player who is multidimensional, who can do a bunch of things,” Bruneau said. “So it makes it fun in practice, because you feel like you have so much to address.”

And from a tactical side, Bruneau added, it’s a different challenge altogether. With an adaptable player who employs an all-court style of tennis, there are seemingly endless possibilities when preparing a strategy. And Andreescu, who in the past has talked about studying her upcoming opponents’ matches, has also proved quick to adapt her own game plan in tough matches.

“It makes it fun in matches because you feel like your game plan can be very elaborate - like there is multi-angles that you can put into the match,” Bruneau explained. “You actually feel like you can go in her game and really pick things that can be really helpful. Because she’s basically, yeah, very able to adapt.

“She likes to change it up and do different things and use the entire court and different angles and spins. She likes to see how her opponents are going to handle some of the shots she makes.”

So far, not many of Andreescu’s opponents have figured out quite how to handle her. She owns a stunning 7-0 record against the WTA’s Top 10 - all of those victories achieved this year - and her 30-4 WTA main draw win-loss record for 2019 is the highest winning percentage of anyone on tour. In fact, Andreescu hasn’t lost in a completed match since February. 

Part of it is due to the inherent advantage of being an unknown quantity. According to Bruneau, the pair typically know more about Andreescu’s opponents than their opponents know about her. But a bigger part of it, he explained, was in Andreescu’s champion ‘DNA’: a drive that makes her see every top opponent as a challenge to puzzle out instead of shrinking away.

Read more: Bianca Andreescu eyes US Open surge: 'I believe that I'm capable of doing big things'

“When she plays opponents who have won Grand Slams or are former No.1 in the world or high seeds and stuff like that, she really felt challenged by it,” he said. “She always looked at it as an opportunity, she was never sort of on her heels from it.

“That goes with her DNA as a person, or as a player. She’s just wired this way.”

Into the quarterfinals of the US Open in her main draw debut, No.15 seed Andreescu will take on the biggest challenge of her career on Wednesday when she faces No.26 Elise Mertens on Arthur Ashe Stadium. 

She is bidding to become the first teenager to reach the semifinal stage at Flushing Meadows since Caroline Wozniacki’s runner-up finish in 2009.