Golden oldies Federer, Hewitt are two of a kind

They're both 31, both turned pro in 1998 and both are still going strong. In the brutally demanding world of tennis, Roger Federer and Lleyton Hewitt are inspiring symbols of longevity.

Remarkably, the veteran Swiss star and his Australian counterpart are both lining up for their 55th Grand Slam at the Australian Open this week, more than any other current player.

Since they kicked off their careers in 1998, their paths have crossed repeatedly, but injuries have hampered Hewitt's progress with just two Grand Slam successes to Federer's 17.

The Swiss has won 76 ATP Tour titles to Hewitt's 28, and earned US$57 million dollars more than the Australian in prize money. But the respect between the two, who both now have young families, is mutual.

On the eve of the Australian Open, Federer hailed Hewitt's resilience and said he had nothing but praise for the Australian, who has dropped down the rankings to 81 but won the Kooyong Classic warm-up tournament on Saturday.

"I am one of the guys who has always believed in Lleyton, even though people were writing him off and being negative and all that stuff... The guy has given everything and more to Australia, to tennis," he told Australian Associated Press.

"I can't stand it when they did that to Lleyton. The guy has given everything and more to Australia, to tennis. He's done a lot. So I admire that he's still playing, that he loves it.

"We're in a similar situation now with both of us having a family. Rankings are not important for him, but he knows he can hang with the best and he can cause upsets and still win tournaments.

"And as long as he feels that way, I hope he keeps on playing and I hope he stays injury-free for once for an entire year because that then would give him great opportunities more often than not during the year."

Hewitt is playing in a record 17th consecutive Australian Open, three more than closest challenger Federer, and is proud to have lasted the distance alongside perhaps the greatest player ever to have graced a tennis court.

"I've missed a lot more Slams than Rog, too. I started before him," he said. "I've had a few more injuries than Rog and had to come back from a few surgeries, which is pretty tough.

"But to play 17 Australian Opens in a row, main draw in singles, is something not easy to do.

"To be fit, I haven't been 100 percent for all of them, but in terms of the staying power, being able to play through generations, is something I'll look back on and be pretty proud of."

Neither man has any plans to retire, with Federer playing fewer tournaments in 2013, focusing on the majors, to help extend his shelf-life.

"Longevity has always been something that's been important to me," he said.

"I've planned the season accordingly this year again, that I will not miss the majors because of injury."

Hewitt, long known for his tenacity and passion, also shows little sign of calling it a day.

Asked if the thought had crossed his mind that this Australian Open could be his last, he replied simply: "No."