Wladimir Klitschko has confirmed he is still coming to terms with the loss of trainer Emanuel Steward, who died last month aged 68.
Klitschko defends his IBF, WBO, IBO and WBA super world heavyweight titles for the first time without the legendary trainer in his corner when he faces Poland's Mariusz Wach in Hamburg on Saturday night.
Steward began looking after the Ukrainian fighter from 2004 and helped him to secure several world titles during their eight-year association.
"It was very sad and it is still sad. The relationship between Emanuel and me was very special," said Klitschko.
"Not just a regular relationship between a coach and a boxer, I assure you of that, because he respected my experience inside and out of the ring.
"I respected his experience outside of the ring as a coach.
"I can tell you that the real spirit of Emanuel Steward is with us. I am very happy there is a fight so we can stay focused and continue to do what he was excited about."
Johnathon Banks will replace Steward in Klitschko's corner against Poland's Wach, who has a record of 27 professional wins from as many fights, including 15 knockouts.
Wach is one and a half inches taller than his 6'6" opponent and Klitschko believes he will provide a stiff test in the 13th defence of his world title.
"I think it is going to be a real exciting fight because Wach has the spirit of a young man that wants to become world champion," added Klitschko.
"He is very self-confident and I am expecting him to be better than he usually can be because that is his motivation - his chance to be world champion and I am expecting a very good fight."