Shane McGuigan admits David Haye still enjoys the occasional 'late night' but is full of praise for the former world champion's attitude.
Haye (27-2-KO25) ended three-and-a-half years out of the ring when he began life under McGuigan with a first-round stoppage of Mark de Mori in January and is currently preparing to face Arnold Gjergjaj (29-0-KO21) at The O2 on Saturday.
Question marks hung over Haye's motivation for returning to boxing at the age of 35 but McGuigan - seven years his junior - insists the approach of the 'Hayemaker' has met the high standards demanded.
McGuigan told Sky Sports: "It's a work in progress with David. I've got to make sure he's doing the correct training outside of boxing, the correct strength training to ensure his body is in balance and firing up.
"When he was fighting before, he was fighting and then going off on holidays a lot because of injuries. He was spending a lot of time away from the gym. Now he's fit and healthy, I want to keep him in the gym as much as possible.
"His reactions and everything are constantly picking up and speeding up. When you've been inactive like he was for three years, you can't just expect to train for three months and suddenly be firing up so for us, it's a work in progress.
"We've been in the gym non-stop and he's enjoying his training, which is the most important thing.
"When he's happy, he's eager to learn and he's in the gym with George Groves, Carl Frampton, Josh Taylor and Conrad Cummings. He's buzzing.
"For the last camp, I didn't want to push him too hard because I didn't know what I could do with him and how he was going to react, but he is just a sponge and he's great to work with.
"Obviously, he likes a late night now and again but that's up to me to make sure that I voice my opinion. I've said to him that 'you do it my way or you don't do it and you find yourself another trainer' and he's thrown himself into it. That's why I feel I'm getting the best results from him."
Haye is likely to hear the opening bell as a resounding favourite against Gjergjaj, and McGuigan sees only one way for the Switzerland-based 'Cobra' to stand any chance of producing an upset.
"Gjergjaj boxed well against Denis Bakhtov because I think he broke his hand early on in that fight. Gjergjaj will probably try and take David into the later rounds by boxing and moving before he starts planting his feet and trying to take him out but it'd be a wrong move.
"Gjergjaj has to let his hands go early on if he's going to have any chance against David Haye."
When asked if the Kosovan-born visitor presented more of a threat than De Mori, Haye added: "He's a lot better. He's got longer reach, is heavier and I expect him to tick all the boxes.
"I'm expecting a tough 10-round fight. If I get a quick knockout then great, but I'm not preparing for it.
"I don't really get fearful from boxing. I'll figure things out when the first bell rings and I get out there and get a feel for him. I'm excited that so many people are coming and it's going to be a good show."
David Haye takes on Arnold 'The Cobra' Gjergjaj at The O2 on May 21. For tickets to #HayeDay visit theo2.co.uk.