They were teammates for club and country, playing the best football of their careers and challenging the world's top players in Europe's leading club competition.
But all was not well behind the scenes between Leeds United duo Mark Viduka and Harry Kewell.
The Australian pair were both key figures in the David O'Leary side that challenged for the Premier League title and rampaged to the Champions League semi-finals in 2001, but Viduka has opened up about how poor the pair's relationship became in a new interview.
"At Leeds, it got to the point, if Harry and I were in the sheds by ourselves, we wouldn't even look at each other," the striker told ESPN. "It was that bad.
"I had a problem with [Kewell's agent] Bernie Mandic. Bernie was my agent when he took me from Celtic to Leeds, but ... I severed ties with Bernie.
"I think maybe our relationship at Leeds wasn't that good because -- and I can't say for sure -- I think that affected the way [Harry] viewed me. [The relationship is better now.] We last spoke in 2013."
The Australians spent three years together at the club before Kewell signed for Liverpool in 2003. Viduka left for Middlesbrough a year later after Leeds were relegated from the Premier League.
During his stint at Elland Road Viduka netted 72 times and remains a firm favourite among the Elland Road faithful. His four-goal haul against Liverpool in November 2000 and a thumping winner against Arsenal in 2003 which effectively secured Leeds' Premier League survival that season were among his high-water marks at Leeds, but his favourite memory in football is a far more humble moment.
"There are so many moments. Everyone assumes scoring four goals against Liverpool would be my highlight or captaining Australia at a World Cup," he says.
"But I'd have to say kicking the ball in the family backyard with my dad will always be my greatest football memory."
