In 2010, Hewitt, with two grand slam triumphs from four finals, two season-ending crowns and 80 weeks as world No 1 after reaching the summit at 20 years and eight months, was voted third-best player of the decade behind Roger Federer and Rafael Nadal.
Roddick came in fifth, with one major from five finals and 13 weeks atop the rankings after peaking at 21 years and two months.
Roddick, married to American actress and model Brooklyn Decker and turning 30 this year, boasts 30 career titles to be 23rd on the open-era leaderboard.
Hewitt, the 30-year-old father of three and happily married to Australian actress Bec Cartwright, has 28 trophies - plus a Gold Logie - on their mantlepiece, to be just behind Roddick alongside Novak Djokovic in equal 24th spot.
If not for grand slam titans Federer and Nadal, Hewitt and Roddick may have dominated the 2000s.
"There are a lot of parallels between us on a lot of levels," Roddick said after sweeping past Dutchman Robin Haase in the opening round.
"We both had success from an early age. We were playing full seasons by the time we were, for him 16, for me 18.
"We're pretty similar in the fact that we always compete pretty well, fight pretty well. He's definitely maximised his game. He's got a great tennis IQ. I think there's a lot of mutual respect there. For sure there is from my end."
For Hewitt, there is indeed respect - and comfort in familiarity facing his long-time foe.
"I don't really have to ask around too much to find out what Andy's strengths and weaknesses are," Hewitt said after turning back unseeded German Cedrik-Marcel Stebe 7-5, 6-4, 3-6, 7-5 to kick-start his record 16th successive Open campaign.
"He's a complete player. He's probably added to his net game a little bit more since the first time I played him, whatever, when he was a 19, 20-year-old, whatever it was.
"His strengths are still pretty much the same. Obviously his serve's his biggest strength.
"For a big guy he moves well. From the back of the court, his forehand is probably stronger than his backhand."
Hewitt celebrated his epic four-hour win over little-known Stebe like he used to celebrate victories over Federer, Nadal, David Nalbandian and the like when it felt like he owned Rod Laver Arena.
He lay prone on his back, ecstatic, like he did when he last conquered Roddick on the very same court in the 2005 Open semifinals.
Hewitt celebrated like this was his farewell Open, having greeted the crowd at the start of the match in the very same way.
Roddick, still close to the top 10, is giving no such indications this will be his last Open. But even after beating the now 181st-ranked Hewitt six straight times, after losing six of their first seven encounters, the American remains on guard.
"When we play, numbers go out the door as far as the number next to our name as far as ranking," Roddick said.
"I don't pay much attention to it when it comes to Lleyton. He knows how to win tennis matches.
"He's a fighter. I have as much respect for him as I do for anybody in the game, how he goes about his business, how he competes, how professional he is.
"I've won the most recent meetings, but I think out of the six that I've won, four or five have gone the distance to the last set.
"We always have a bit of a war. I probably don't see it being any different."
Nor does Hewitt.
"I'll give him a good run," he said. "See what happens."
- AAP
