Rusedski unleashed a furious verbal volley at the umpire during his 7-6, 7-6, 7-5 defeat after a spectator called out during a rally in the third set but the official failed to order a replay of the point.
"I think he had a legitimate argument," said 20-year-old Roddick, who has occasionally struggled to control his own emotions on court in the past.
"It's hard to explain if someone hasn't been in the heat of the moment themselves. It's understandable.
"You're trying so hard, you're putting everything you have into it. For something that you don't really have control over to play a part in the match is very frustrating.
"I can kind of relate to Greg a little bit in that sense."
The 20-year-old fifth seed took full advantage of Rusedski's subsequent loss of concentration, turning a 5-2 deficit into a 7-5 triumph to seal the match.
He added: "I knew he might be a little mad so if I was going to get back into it or try to take over, that was probably my time."
Roddick said he was pleased with his own performance, especially his backhand, against one of the best serve-volleyers in the game in the face of a mostly hostile crowd.
"It's good," he said. "These are the kind of matches that you need to go deep in a grand slam. That wasn't a second-round match out there. He was playing well enough to have gone far into the second week."
But he was dismissive when asked how it felt to be the bookmakers' favourite to win the Grand Slam.
"Bookmakers don't play matches," he snapped. "It's just speculation, dude. It doesn't affect what goes on between the lines."
