Jose Mourinho once called Arsene Wenger a 'specialist in failure' but after the Arsenal manager announced he was stepping down at the end of the season there was only respect.
Asked by reporters whether he regretted some of his behaviour towards the Frenchman over the years, the Manchester United boss suggested the question betrayed a lack of understanding.
"You are not a manager, you are not a player of course," he said. "You do not know the way we respect each other, even when sometimes it looks like in some moments we don't.
"In the end, probably the ones that respect each other more are the ones that have the problems.
"It is power against power, it is quality against quality, it is ambition against ambition."
Wenger, 68, announced on Friday that he will end a near 22-year reign at the north London club, during which he has become Arsenal's most successful manager.
Mourinho's rivalry with Wenger dates from the younger manager's arrival at Chelsea as the self-proclaimed Special One in 2004.
In 2005, the Portuguese famously labelled the Frenchman a "voyeur" after becoming annoyed at comments from him about his Chelsea team.
By 2014, when the 'specialist in failure' comment was made, the rivalry had become so heated that Wenger pushed Mourinho as the pair clashed in the technical area during a 2-0 defeat to Chelsea at Stamford Bridge.
On Friday, Mourinho said he hoped Wenger did not retire from football.
"If he's happy I'm happy, if he's sad, I'm sad," he declared. "I always wish the best for my opponents.
"Mr Wenger and Arsenal were for many, many years the biggest rivals of Sir Alex's (Ferguson) era, I'm pretty sure that we as a club will show Mr Wenger the respect he deserves."
Mourinho, a Premier League title winner with Chelsea, recognised what Wenger had achieved.
"For us football people, the real football people, who are the ones inside the four lines, playing, or the managers ... the football people don't have short memories," he said.
"I know what it means, three Premier League titles and seven FA Cups, what he did in Japan and France, what he brought to French football and what he gave to Arsenal in the period without Premier Leagues, the transition from stadium to stadium.
"We know what he did."