CINCINNATI, Ohio - World No.4 Angelique Kerber already had two Slams under her belt before she won her third last month at Wimbledon, but for her coach Wim Fissette, nothing beats a Wimbledon title. 

"To be honest, I think you can be a Grand Slam champion, or you can be a Wimbledon champion," Fissette told reporters at WTA Coaches Media Day at the Western & Southern Open. "I always feel there's going to be a difference in that. 

"Wimbledon will always be special, the most special Slam of all of them, because if you speak to people on the street they maybe know the Australian Open, but everyone knows Wimbledon. People who don't know about tennis, they know Wimbledon and that's a very special thing. 

"I mean in Germany it was huge. I actually was in a similar situation a few years ago with Sabine Lisicki when she was the first one after Steffi Graf who played a final of a Slam, which was always huge. It's very good I think for tennis in Germany and it will give tennis in Germany a huge boost."

After a disappointing 2017 that saw Kerber start the year at No.1 and finish outside the Top 20, the German brought on Fissette last November to help her rediscover the form that won her the Australian Open and US Open in 2016. The Belgian veteran coach, who has worked with Kim Clijsters, Simona Halep, Victorka Azarenka and Johanna Konta, says he never hesitated when he got Kerber's call. 

"As soon as I got the phone call to work with Angie I was convinced because I've seen her play so many times. I have played so many times against her as a coach and I always believed in her potential and she could even do better than she did in the past. I still believe and I still see and I feel there's room for improvement." 

With the US Open less than two weeks away, Fissette's concern is less about improvement and more about getting Kerber back to stasis. Kerber took a two-week break after Wimbledon and the two began practicing again 5 days before the start of the Coupe Rogers. Kerber lost her opening match 6-4, 6-1 to Alizé Cornet in Montreal, but the loss hasn't left the team too concerned.

"I mean if you have a dream in your life and suddenly you've fulfilled that dream, it's never easy and you need a bit of time with that, Fissette said. "But you also don't know how much time you're going to need and how are you going to feel on the court. 

"But I can only say for now she's putting in all the work. Everything that we ask for and I'm very pleased with that. If she will continue like that she's going to get better."

Despite being a three-time Slam champion and former No.1, there remains a sense that perhaps Kerber's talent is underrated by the public. That's not too much of a concern for Fissette. He knows Kerber's reputation in the WTA locker room is second to none and that's all that matters. 

"She's not the most spectacular player," he said. "You have other players that are spectacular, but Angie, I call her rock solid. She's maybe not the player that you think is a three-time Slam champion but everyone hates to play her. I had that in the past years. Every time we had to play Kerber we were like, ooh. Hmmm. 

"She's just a very tough player to play because normally she doesn't make many unforced errors but if you don't put a lot of pressure then she's the one who's putting the pressure because she can do all of it. She can play great defense, she can play great offense. 

"Her serve, I feel now has improved but still also in the past, it was never easy. People were saying she doesn't serve well, but still it was a tough one.  Especially with the lefty slice, it was still a tough serve. 

"I feel Angie as a player, that she deserves to have three Grand Slams. She's been in the Top 10 a lot of years. She always brings her best effort. She always fights until the last ball. I feel especially with the improvement in the past years -  I mean she wasn't 21 when she won her first Slam - she always brought the work and became better every year. I think this is a great example for a lot of players."