The Swede began working with Wawrinka in 2013, and since then the Swiss has seen his career skyrocket. Wawrinka has reached a career-high of World No.3, won three Grand Slams and competed at the Nitto ATP Finals four times. Even more impressive is that he has had to compete against the "Big 4" during this period of time.

“Stan is one of the best players to ever play the game, if you look at his record, if you look at winning three Grand Slams, winning three different Grand Slams in the era where he had the Big Four playing,” Norman told ATP Tennis Radio. “He’s a little bit underestimated for sure, and he’s been in numerous semi-finals as well, another Grand Slam final. He’s had an unbelievable career.”

The Swiss has had a difficult journey over the last three years, having undergone two left knee surgeries in August 2017. This saw his ranking drop to as low as World No.263, and he has struggled to rediscover his top form.

“It’s been a little bit up and down. He doesn’t have the same stability as Andy Murray or Novak or Roger or Rafa, but in his best moments, I think he can beat all of those names on a very good day,” Norman said. “That’s what makes him a little bit special, also. You don’t really know which Stan to expect on the day or on that occasion, and that’s why I think a lot of people really like him.”

Norman concedes that Wawrinka has his ups and downs, which could make him frustrating to coach. However, this is due to his aggressive play, which makes him even more dangerous.

“Stan is a gambler. He plays with small margins. He’s the kind of guy that will put everything in red, do or die,” Norman said. “This is his personality a little bit, so I think it’s very tough to change his personality. But I also think that’s the reason why he won three Grand Slams. He can rise to the occasion. He can go for shots that normally someone else will play a little bit safe. That makes him that dangerous, I think.”

Norman plans to meet with Wawrinka in Monaco to prepare for the upcoming American hard-court season. Both men have high expectations for the summer.

“If he can play a good match, if he can play good tennis, it’s going to take a lot to beat him,” Norman said. “He’s that good.”

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