NEW YORK, NY, USA – No one knows Angelique Kerber’s game as well as Torben Beltz. The 39-year-old has coached the now two-time major champion and new World No.1 since she was 16-years-old, and though they’ve had their breaks apart, the decision to resume their partnership in the Spring of 2015 has paid nothing but dividends.

After reuniting before the BNP Paribas Open last march, Kerber went on to win four Premier titles in Charleston, Stuttgart, Birmingham, and Stanford. By the end of the year, no one had won more matches than Kerber. But after a disappointing season at the Slams and a pressure-soaked loss to Lucie Safarova at the BNP Paribas WTA Finals Singapore presented by SC Global to end the year, the two set their sights on the majors.

And the rest, as they say, is history.

WTA Insider caught up with Beltz the day after Kerber’s New York triumph, to discuss how Team Kerber got to this point, the keys to their success, and what they’re looking to build on going forward.

Listen to the full interview on the WTA Insider Podcast:

On trying to keep a relaxed atmosphere around Kerber:

I think it’s very important to keep her relaxed, especially here. When she was playing against Caroline Wozniacki, it was clear she was already No.1, but I thought it wasn’t good to make a big deal out of this because she had to play Caroline in the next five minutes. We really tried to keep it relaxed then, which was not so easy to be No.1 and be relaxed!

But we kept it easy, and I told her, ‘You have to focus on the match, because against Caroline, it’s going to be a very tough match.’ You could see there were a lot of long rallies and she had to play her best tennis. But she was focused again, and I think it’s working out very good.

On whether Kerber’s 2016 was a surprise:

We all knew that she was going to be a very good player. I knew that before. But I have to say after this year, it’s for sure surprising to be in three Grand Slam finals. We cannot take that for granted. I knew she could play very good tennis; I knew her when she was young and outstanding in Germany. We all knew she could play very good, but it’s incredible and amazing for me. It’s a good story.

On Kerber’s work ethic:

Success doesn’t come from nothing; you have to work every day. As a player, you have to sacrifice and a lot, and I think she’s earned what she’s getting now. It’s a day-to-day process, as well, like in the off-season, we worked on the serve. We tried to work hard every day, trying to figure out new things, something special so it’s not too boring after eight weeks. But we did a good job, and we’re happy.

On how he came to be Kerber’s coach:

Our first meeting was when she was 12 or 13 in Germany. She was winning U18 Nationals at 15. She was outstanding, but in the beginning, she was such a talented girl, who knew where the ball was coming. She wasn’t working that hard at the time, when she was young. But it really changed, and that’s why she’s playing so well at the top level.

The first time we met, the family and coaches were looking for somebody who would help her take the first steps onto the pro tour. She was ranked around No.300 and finished with school, so they needed someone who was young and liked to travel, and could play decent tennis! So I came in to help her play some 25Ks, some junior tournaments. We started when she was around 16, 17, for one or two years. Then she had a shoulder operation, and we stopped. We came back around 2011, after being on and off for quite a time. It’s fun to work with her; she’s pretty good.

On the challenges of coaching Kerber:

“It’s a big challenge, and never gets boring. We’re always looking at new things, every day. There are always improvements to make, where for me as a coach, the job is never finished. She’s No.1, won Grand Slams, but it’s not finished; there are still things to work on. For me, it’s perfect to see that, and we’re happy to go to the next step. Right now, she’s won a Grand Slam and I can say it’s easy, but when she’s frustrated in practice or losing, it’s not always easy. But we have a good way to talk about things; we solve problems together. Our communication is good.”

On losing a “hairy” bet with Kerber:

I saw two players at a golf tournament, where they had a bet not to shave, and I told Angie that if she won the US Open, I wouldn’t shave my mustache for the five or six weeks of the Asian Swing. So, it’s not going to look that great, but let’s see. It’s worth it for the Slam. We’ll see what happens.

All photos courtesy of Getty Images.