Day 7 at Melbourne Park was a day of new marks for the majors.
Federer equaled Jimmy Connors' mark for consecutive Grand Slam quarterfinals appearances when he beat Tommy Robredo 6-3, 3-6, 6-3, 6-2 on Sunday. The 16-time Grand Slam winner has now reached the quarterfinals at 27 majors in a row since 2004.
Connors reached the quarterfinals in 27 consecutive majors he entered between 1973 to 1983 - although he missed 13 Grand Slam tournaments during that period of time either through injury or because he didn't travel to Australia.
French Open champion Schiavone established a Grand Slam women's record later Sunday, needing 4 hours, 44 minutes to beat Svetlana Kuznetsova 6-4, 1-6, 16-14 in a fourth-round match. Schiavone saved six match points, then converted on her third match point in the longest match at a major in terms of time in the Open era.
The longest previous women's match in a Grand Slam tournament was here last year when Barbora Zahlavova-Strycova beat Regina Kulikova 7-6 (5), 6-7 (10), 6-3 in a match lasting 4:19.
The 30-year-old Italian said she was almost exhausted but, "at the end, you have something more, always."
"Was for me, fantastic," she said. "When you're in a situation like this, every point is like a match point. You have to keep going. You know that physically you're tired. Mentally just keep going."
Kuznetsova said the match was so long she was forgetting the score or who should serve.
Schiavone said it wasn't quite that bad for her, "but I was watching the clock, and I say - 'Bravo, Francesca, you are tough!"
Schiavone will meet top-ranked Caroline Wozniacki in the quarterfinals.
Shortly after, 2008 champion Maria Sharapova lost 6-2, 6-3 to Andrea Petkovic, who had a relatively easy run into the fourth round when Venus Williams retired after just four minutes in their third-round match.
Petkovic will now take on China's Li Na in the quarterfinals.
"Maria is such a great champion, it's just two or three points and she comes back, and she started playing so well in the last couple of games, so I was a little nervous," Petkovic said. "But I am happy I closed it out in the end."
Federer didn't concede a point on his serve in the first set, but had a lapse in the second when Robredo's serve was dominant and he took a set off Federer for only the third time in 10 matches.
"I was struggling with my return - I couldn't get the balls into play I wanted to," Federer said. "I didn't have the best of games at 4-3 down - we don't have much margin at the very top and it shows."
Federer regained control in the third set and dominated after getting an early break to lead 2-0.
"It's a lot of hard work. I'm sweating bullets right now," he said. "I'm excited to be in the next round."
He admitted he'd had a tough first week, including a five-set win over Gilles Simon.
"I'm in another quarterfinal. Got all the chances to make it to the semis again," Federer said, "so I'm very pleased."
Federer, aiming to be only the second man to win five Australian Open titles, will play either Andy Roddick or 19th-seeded Stanislas Wawrinka of Switzerland in the quarterfinals. Roddick and Wawrinka play their fourth-round match Sunday night.
No. 3-ranked Novak Djokovic is aiming for his second Australian crown. The 2008 champion advanced to the quarterfinals for the 13th time in the last 15 majors with a 6-3, 6-4, 6-0 win over No. 14 Nicolas Almagro and will next play last year's Wimbledon finalist Tomas Berdych, who beat Fernando Verdasco 6-4, 6-2, 6-3.
The 20-year-old Dane, playing her first major as world No. 1, can keep her top ranking with an appearance in the semis.
The questions about Wozniacki's worthiness of the top ranking are starting to diminish. Asked which player she feared most, she said: "I don't fear anyone actually."
"I'm feeling confident. I feel like I can beat anyone on a good day. I think they have to fear me when they're playing me," she said. "I just go out there and do my best. If they're better than me that day, it's just too good."
Wozniacki lost three of the first four games of the match before reeling off six in a row, including a break in the first game of the second set. Sevastova, ranked No. 46, rallied and the pair traded breaks until Wozniacki regained control.
Wozniacki now has reached the quarterfinals at all four majors, and she's navigated some troublesome ground. According to the WTA, only one of the last five women to be ranked No. 1 went beyond the first round in the first major they played with the top ranking.
She also steered herself in and out of trouble after telling a story in a post-match news conference about being scratched by a kangaroo.
After her match, she described an up-close encounter with a baby kangaroo that had scarred her.
She said she tried to pet the kangaroo and it scratched her, and noted she had seen a doctor and rejected advice to get stitches.
But she later tweeted: "Round 2 with the media:) hope you enjoyed my kangaroo story, hope you know i was just kidding:) see you on tuesday for round 3!"
She later returned to Melbourne Park to clarify she'd made up the story and to apologize, saying she didn't think anyone would believe it.
Li, already China's most successful player, reached the quarterfinals with a 6-3, 6-3 win over eighth-seeded Victoria Azarenka of Belarus.
The ninth-seeded Li was one of two Chinese players to reach the semifinals at Melbourne Park last year, her run ending with a loss to eventual champion Serena Williams in two tiebreak sets.