AS a tour player, Josh Eagle was a contemporary of Pat Rafter and later he was coach of Aussie Davis Cup teams spearheaded by Lleyton Hewitt.
And Eagle says his new charge, Sam Stosur, loses nothing by comparison with the former world No.1 players in terms of work ethic in training.
The duo is preparing for as many as 25 weeks together on the WTA Tour next year, with the first stopover at the Brisbane International from Sunday.
Eagle insists Stosur's capacity to embark on a hot streak of form makes her a grand slam contender even if at No.21 in the rankings she has a battle with Daria Gavrilova (25th) to hold on to her Australian No.1 mantle.
"All those great champions - and I think that's anyone who's won a grand slam title like Sam - get where they do by sheer hard work,” Eagle said.
"I've seen at the two tournaments I travelled with her last year, and during the pre-season, how dedicated she is and still how willing she is to embrace change. Her training at her age is about trying to do it smarter.”
To illustrate her willingness to step out of her comfort zone, Stosur and Eagle decided only three days ago on a new combination of racquet weight and string tension he wants to enable her to hit the ball harder.
Casual fans who have watched Stosur's big, kick serves and heavy forehand may wonder why she needs to hit the ball harder, but she and Eagle believe she needs to get rid of some of her "spinny” groundstrokes.
"In certain conditions, I find it difficult to generate pace - so many girls are so powerful and hit the ball so hard that I feel like I'm the one behind the eight ball,” Stosur said.
"I hope it's a productive year. You have to make changes from time to time and I enjoy what he has to tell me on the court.”
Stosur ended her second long stint with David Taylor, who coached her to the 2011 US Open triumph, in June following a French Open semi-final berth.
The former world No.4 was coached by Andrew Robertson in the grasscourt season, Eagle during the American hardcourt circuit and Rennae Stubbs assisted her in Asia late in the season when Eagle was unavailable.
"I believe in her. She has a lot of upside,” Eagle said.
"The fact she made the semi-finals at the French Open proves to everyone she is capable of potentially winning another grand slam. We have to tidy up a few areas.”
Stosur is unseeded in her seventh Brisbane International, at which she is yet to make a quarter-final, and could be drawn against one of five top-10 players in the first round.
"There are other options to play, but I'm not going to run away from Brisbane because I haven't won as many matches here in the past as I'd like,” Stosur said.