Highlights from Australian Open day three: Dimitrov survives scare as Wozniacki put on a stunning comeback

Third seed Grigor Dimitrov suffered a huge scare against 186th-ranked qualifier Mackenzie McDonald before holding his nerve in a tension-charged deciding set to win 4-6 6-2 6-4 0-6 8-6 and reach the third round of the Australian Open on Wednesday. Bulgarian Dimitrov, a semi-finalist at Melbourne Park last year, fell in a huge hole in the fourth set against the free-swinging American, whose shot-making and composure made a mockery of his humble ranking. Dimitrov had to wait and hope for McDonald to falter under the lights at Rod Laver Arena, and finally the American did with a double-fault that gave up match point.KYRGIOS POWERS PAST TROICKIHome favourite Nick Kyrgios, seeded 17th, fired 17 aces to see off Serbian Viktor Troicki 7-5 6-4 7-6(2) in the second round. He will next face 15th seed Jo-Wilfried Tsonga.WOZNIACKI COMPLETES STUNNING COMEBACKWorld number two Caroline Wozniacki roared back from 5-1 down in the final set, saving two match points, to beat Croatian Jana Fett 3-6 6-2 7-5. "I'm very proud of the way I came back. I just tried to mentally stay focused. It was very hard, and she was playing well," Wozniacki said after the match."All of a sudden seeing myself down, almost out of the tournament, I started playing better and started playing the tennis that I wanted to play.CILIC EASES INTO ROUND THREESixth seed Marin Cilic hit 40 winners, including 20 aces, on his way to a 6-1 7-5 6-2 second-round victory over Portugal's Joao Sousa.Cilic will next face American Ryan Harrison, who beat Uruguay's 31st seed Pablo Cuevas 6-4 7-6(5) 6-4.TSONGA BATTLES PAST SHAPOVALOV IN MARATHONFormer Australian Open finalist Jo-Wilfried Tsonga came back from 5-2 down in the final set to beat Canadian teenager Denis Shapovalov 3-6 6-3 1-6 7-6(4) 7-5 after three hours and 37 minutes of play.SVITOLINA SURVIVES SINIAKOVA SCAREFourth seed Elina Svitolina came from a set down to beat Czech Katerina Siniakova 4-6 6-2 6-1 and book a spot in the third round. Ukrainian Svitolina will next face 15-year-old compatriot Marta Kostyuk, who beat Australian wildcard Olivia Rogowska 6-3 7-5. She is the youngest player to reach a grand slam third round since Mirjana Lucic-Baroni at the 1997 U.S. Open."I remember being at that age. No pressure. Second round, creating history and all that," the 26-year-old Rogowska said. "She (Kostyuk) came out firing so credit to her. She's going to be a really good player."CARRENO BUSTA INTO ROUND THREEPablo Carreno Busta, a U.S. Open semi-finalist last year, is the first player from the men's field through to the third round after the 10th seed's opponent, Gilles Simon, retires hurt while trailing 6-2 3-0.PAVLYUCHENKOVA UPSET BY BONDARENKOAnastasia Pavlyuchenkova, the Russian 15th seed, has been knocked out by Ukraine's Kateryna Bondarenko in a 6-2 6-3 second round upset on Hisense Arena. "I am really happy, I don't really like playing first match but I guess it worked okay today," said the world number 94.