MELBOURNE, Australia (AP) Defending champions Novak Djokovic and Serena Williams are back on court Friday for their third-round matches at the Australian Open.
Six-time champion Williams is playing Russian teenager Daria Kasatkina.
Djokovic, seeking his sixth Australian Open title, plays No. 28-seeded Andreas Seppi. Djokovic has never lost in 11 career meetings with the Italian player, including a straight-set victory in the third round of the U.S. Open last year, but he's not taking anything for granted.
''He likes playing here,'' Djokovic said of Seppi, who has advanced to the fourth round in two of the past three years. ''He's not really overwhelmed by a big occasion.''
If Djokovic gets past Seppi, he could face Gilles Simon in the fourth round and potentially Kei Nishikori in the quarterfinals - if Nishokori wins his third-round match Friday against No. 26-seeded Guillermo Garcia-Lopez.
Here are some other things to watch on Friday:
SISTER ACT: Serena will have a chance to exact some family revenge on Kasatkina, who beat Venus Williams in an Australian Open warm-up tournament at Auckland last week. ''I don't think it's going to be easy,'' Serena Williams said of her night match at Rod Laver. "Any time someone is beating Venus they are more than likely playing really good.'' Serena has never played Kasatkina, so will do some advance scouting. ''I obviously will ask Venus what she thought of the match, and I'm sure Patrick (coach Patrick Mouratoglou) will know everything about her match and stuff. He's really good at studying.''
FEDERER AND MORE: Roger Federer and Grigor Dimitrov meet for the second time this month when they play their third-round match on Rod Laver Arena. Dimitrov, who has a similar playing style to the Swiss star and was even nicknamed ''Baby Fed'' when he first came on tour, hasn't beaten Federer in four meetings. In fact he hadn't taken a set from Federer until the Brisbane International two weeks ago, when he lost in three sets. Federer lost the Brisbane final to Milos Roanic and Dimitrov went on to make the Sydney International final. ''Obviously it's not an easy match, but I feel that I've been playing good and have quite a few matches behind my back already,'' Dimitrov said. Federer was suffering from flu and cold symptoms at Brisbane. ''Brisbane overall was tough to judge in the sense that I was just playing within myself, trying to sort of get through the matches without too many long rallies,'' Federer said. ''I think he did well in Sydney, and that definitely also gave him a bit of a lift if he takes the positives out of the tournament ... so he's on a high right now.''
SERENA IN SIGHT: Fifth-seeded Maria Sharapova plays Lauren Davis, and a win would keep her in with a chance of facing Serena Williams in a quarterfinal featuring last year's finalists. Sharapova hasn't played Davis but goes into the match fully recovered from a left forearm injury that forced her to withdraw from the Brisbane International, where she was defending champion. ''I feel pretty good, I felt I was more confident with my left hand today,'' Sharapova said after her second-round win. ''That's always something that especially when it's like in the hand/wrist area, it's in the back of your mind even though you're feeling it.'' Davis advanced on Wednesday when Magdalena Rybarikova retired after losing the first set.
LOCAL FLAVOR: Australia's 29th-seeded Nick Krygios plays Tomas Berdych. The winner of that match next plays either former U.S. Open champion Marin Cilic or Roberto Bautista Agut. The last remaining Australian female in singles, Russian-born Daria Gavrilova, who beat sixth-seeded Petra Kvitova in the second round, plays Kristina Mladenovic.