(CNN) -- Roger Federer and Novak Djokovic eased into the third round of the Australian Open on Wednesday as 10th seed David Nalbandian of Argentina made a shock exit.
Nalbandian has not won a grand slam in 29 attempts and crashed out to Lu.
World number two Federer was untroubled in a 6-2 6-3 6-1 win over Russian qualifier Evgeny Korolev while defending champion Djokovic brushed aside Jeremy Chardy 7-5 6-1 6-3.
But Nalbandian, winner of the pre-tournament Sydney International, lost in a marathon match to Taiwan's Yen-hsun Lu.
The 25-year-old Lu prevailed after nearly four hours, 6-4 5-7 4-6 6-4 6-2 to reach the third round of a grand slam for the first time in 13 attempts.
"I just had nothing to lose today, because he's top 10 player," Lu was quoted on the official tournament Web site www.australianopen.com. "For me, I'm 61 in the world and I have no pressure. I was just going on the court and playing my game and it's not about who is better.
"But today for sure I'm better performance than him. I think I serve also more consistent than him. After the fourth set and final set I played more aggressive than him. So that's the key point I can take in this match."
Earlier, Federer stepped up a gear from his opening match at Melbourne Park to quickly impose himself on qualifier Korolev, who had beaten former world number one Carlos Moya in the first round.
He needed just one hour and 27 minutes to earn an eagerly-awaited last 32 clash with Marat Safin, who beat the Swiss star on the way to his 2005 Australian Open title.
"It's going to be a nice match for sure," the 27-year-old said.
"We have a history. We have played a few times. We've played in majors before and played some good matches before and in the Davis Cup as well.
"So we go way back. He, of course, is a former number one, the same for me, and a former grand slam champion, it's an intriguing match-up."
Safin, the 26th seed, beat Guillermo Garcia-Lopez 7-5 6-2 6-2 and is looking forward to a rematch with Federer. We know each other well. He knows how to play against me and I know how to play against him.
"Unfortunately I didn't win a lot of matches against him but I'm looking forward to it," said the Russian. "I have nothing to lose. I'm going to go for it and whatever comes, comes."
Djokovic, who struggled in warm-up tournaments in Brisbane, is running into better form and never looked back after gaining the crucial break in the 12th game of the first set against Frenchman Chardy.
"I'm playing better and better which is very encouraging for me.
"I really stepped it up today and played pretty good in the second and third set especially, " said the Serbian who will play Amer Delic in the third round after he came back from two sets down to shock 28th seed Paul-Henri Mathieu 1-6 3-6 6-3 7-6 9-7 in an epic battle.
In Wednesday's evening session, seventh seed Andy Roddick came from a set down to beat dangerous Belgian outsider Xavier Malisse, 4-6 6-2 7-6 6-2.
Eighth seed Juan Martin del Potro of Argentina also went through as he beat Florian Mayer of Germany, 6-1 7-5 6-2.
Other seeds to progress on Wednesday were 11th seed David Ferrer, No.15 Stanislav Wawrinka, 20th seed Tomas Berdych and 21st-ranked Tommy Robredo.