Australian Open Day 7 matches to watch

Novak Djokovic (pictured) has won 10 in a row against fourth-round opponent Stan Wawrinka. (Graham Denholm/Getty Images)

Storylines and matches to watch on Day 7 of the Australian Open (click here for the order of play):

• Serbian Sunday: The Serbian fans will be out in full force as Novak Djokovic and Ana Ivanovic will anchor the night session on Rod Laver Arena, likely with split results. Ivanovic is up first against Agnieszka Radwanska, who has yet to drop a set this year in 12 matches. "I'm very confident from the beginning and just happy that I can play really my best tennis from the beginning of the year," Radwanska said. Radwanska has won four consecutive meetings after losing the first three, with all of Ivanovic's victories coming before 2009. It's a much better story for Djokovic, who takes on Swiss No. 2 Stanislas Wawrinka. Djokovic hasn't lost to Wawrinka since 2006, a string of 10 matches.  There's no reason to think that's going to change here.

• Sharapova back in action: After an intense walloping of Venus Williams in the third round, Sharapova will face the unseeded and 43rd-ranked Kirsten Flipkens. The 27-year-old Belgian, who has made the Round of 16 at a Grand Slam tournament for the first time, shouldn't pose much resistance. Sharapova hasn't been doing much wrong through the week, serving and returning as well as we've seen in some time and hitting big off the ground. Flipkens simply has nothing that can bother Sharapova, who has conceded four games in three matches. "I think the reason I started so well in this tournament is because I knew that I had to," Sharapova said. "I knew I was coming in without any match play. It's tough. I hadn't played a real match in over two months. Coming into a Grand Slam, it's not always the best-case scenario. I've been experienced enough to manage that."

Matches to watch

• No. 1Novak Djokovic vs. No. 15 Stanislas Wawrinka (second night match, Rod Laver Arena): This match may tilt solidly in Djokovic's favor, but it's worth tuning in to see how he fares against a top-20 opponent. The defending champion hasn't lost a set or been broken in his first three matches. So does the gap between him and the field appear just as wide when he plays the 17th-ranked Wawrinka?

Agnieszka Radwanska hasn't dropped a set in 12 matches this year. (Paul Crock/AFP/Getty Images)

• No. 8 Janko Tipsarevicvs. No. 10Nicolas Almagro (third match, Hisense Arena): Odd to see that these two veterans have played only once, a straight-set victory for Almagro in the fourth round of last year's French Open. This should be the most hotly contested match of the day. While Almagro struggled through a five-setter in the first round, he won his next two matches in straight sets. Tipsarevic has taken the opposite path, playing his best in the first round against Lleyton Hewitt before getting bogged down in back-to-back five-setters against Lukas Lacko and Julien Benneteau. Tipsarevic prides himself on his fitness, but expending this kind of energy in the first week can add up. I like Tipsarevic to come through on the hard courts, but if this goes the full five, Almagro's fresher legs will take over.

• No. 4 Agnieszka Radwanskavs. No. 13Ana Ivanovic (first night match, Rod Laver Arena): A winner of 24 sets in a row this year, Radwanska is the heavy favorite. She has the ability to keep the ball out of Ivanovic's strike zone and keep the Serb on the move. That said, Ivanovic is playing as well as she has since 2008, striking the ball with good consistency off the ground.

• No. 5 Tomas Berdych vs.Kevin Anderson (fourth match, Margaret Court Arena): Anderson has had a tremendous start to the season, making the final in Sydney and upsetting Fernando Verdasco in the third round here to advance to the Round of 16 for the first time at a major. He's not as solid as Berdych off the ground, but if Anderson and continue to serve effectively and force the sets into tiebreakers, he will have a great chance at the upset.

No. 6

Li Na vs. No. 18 Julia Goerges