MELBOURNE, Australia -- The fourth round of the Australian Open begins Sunday. Here are the matches to watch on Day 7. Tennis Channel will have two hours of coverage starting at 7 p.m. ET, and ESPN2 will take over at 9 p.m.
Serena Williams  vs. Ana Ivanovic  (Second match, Rod Laver Arena): Ivanovic hasn't won a set against Williams in four meetings, but the Serb is on a roll after winning a tune-up tournament in New Zealand and reaching the fourth round here with a strong performance against Sam Stosur. Ivanovic will need to continue to find the range on her forehand to challenge the five-time champion, who hasn't dropped a set yet. "Serena is on top of the game for so long now," Ivanovic said. "She's someone we admire actually. It's going to be very tough task. But I look forward to that challenge. I've been playing some good tennis. It's going to be nice test to see where I'm at."
Novak Djokovic  vs. Fabio Fognini  (Third match, Rod Laver Arena): The three-time defending champion is riding a 27-match winning streak and says he's "playing better and better" as the tournament progresses. This will be his first match against a seed; Fognini, who is enjoying his best Australian Open, has never beaten Djokovic in six attempts.
Stanislas Wawrinka  vs. Tommy Robredo  (Second night match, Rod Laver Arena): Wawrinka should be fresh for this clash of resurgent veterans with one-handed backhands. The Swiss played only a set and a half in the first round before Andrey Golubev retired, and he received a walkover in the third round after Vasek Pospisil's withdrawal. Robredo, meanwhile, outlasted Lukas Rosol 8-6 in the fifth set of the first round and scored four-set victories over Julien Benneteau and No. 9 Richard Gasquet. Robredo leads the head-to-head 6-1, including 2-0 last year, when the Spaniard beat Wawrinka on a hard court at the Western & Southern Open.
Li Na  vs. Ekaterina Makarova  (Second match, Hisense Arena): Li, a 2013 finalist, saved a match point in her third-round escape against Lucie Safarova. She figures to get another test against Makarova, who is one win away from her third consecutive quarterfinal appearance. Li defeated Makarova in three sets at the U.S. Open last year, improving to 4-0. Eugenie Bouchard  vs. Casey Dellacqua (First night match, Rod Laver Arena): One of these players will make her first Grand Slam quarterfinal. Bouchard, 19, seeded for the first time at a major, continues her steady climb into the upper levels of the WTA Tour. Dellacqua, 28, an Australian wild card ranked No. 120, has matched her career-best fourth-round run at the 2008 Australian Open. "When I made it in '08, it was such a whirlwind," Dellacqua said. "I didn't get much time to take much of it in. ... Now, I've had to work really hard and I'm a little bit older and a bit more mature and able to take everything in a bit more. I definitely feel like a better player than in '08." This will be the first meeting between Bouchard and Dellacqua, neither of whom has lost a set here.