Melbourne - Sixth seed and last year's Australian Open runner-up Marin Cilic ground out a tough four sets win over American Mackenzie McDonald to move into the third round on Thursday.
The Croat, who lost an epic final in five sets to Roger Federer a year ago, needed 3 hours and 37 minutes to get past the 23-year-old 7-5, 6-7 (9/11), 6-4, 6-4.
"Every single time the atmosphere here is amazing," said Cilic, who has been struggling with a knee injury.
"Mackenzie played unbelievable tennis today, he was hitting from the back ridiculously well. I had to work hard to win this one and I'm extremely pleased."
The former US Open champion, who will next play either Spanish 26th seed Fernando Verdasco or Radu Albot of Moldova, said the knee was still not 100 percent.
"It's getting better but I feel that if could improve, so I'm hoping with a couple of matches and getting used to the conditions it's going to get better," he said.
"I'm hitting the ball well and enjoying my time on the court and these two matches have been great for me."
Results from Day 3 of the Australian Open on Wednesday:
Men's singles
Second round
Stefanos Tsitsipas (GRE x14) bt Viktor Troicki (SRB) 6-3, 2-6, 6-2, 7-5
Nikoloz Basilashvili (GEO x19) bt Stefano Travaglia (ITA) 3-6, 6-3, 3-6, 6-4, 6-3
Tomas Berdych (CZE) bt Robin Haase (NED) 6-1, 6-3, 6-3
Andreas Seppi (ITA) bt Jordan Thompson (AUS) 6-3, 6-4, 6-4
Diego Schwartzman (ARG x18) bt Denis Kudla (USA) 6-4, 7-5, 3-6, 6-7 (6/8), 6-4
Marin Cilic (CRO x6) bt Mackenzie McDonald (USA) 7-5, 6-7 (9/11), 6-4, 6-4
Frances Tiafoe (USA) bt Kevin Anderson (RSA x5) 4-6, 6-4, 6-4, 7-5
Fernando Verdasco (ESP x26) bt Radu Albot (MDA) 6-1, 7-6 (7/2), 6-3
Karen Khachanov (RUS x10) bt Yoshihito Nishioka (JPN) 6-3, 6-3, 6-3
Roger Federer (SUI x3) bt Daniel Evans (GBR) 7-6 (7/5), 7-6 (7/3), 6-3
Taylor Fritz (USA) bt Gael Monfils (FRA x30) 6-3, 6-7 (8/10), 7-6 (8/6), 7-6 (7/5)
Roberto Bautista Agut (ESP x22) bt John Millman (AUS) 6-3, 6-1, 3-6, 6-7 (6/8), 6-4
Grigor Dimitrov (BUL x20) bt Pablo Cuevas (URU) 6-3, 6-7 (5/7), 6-3, 7-5
Thomas Fabbiano (ITA) bt Reilly Opelka (USA) 6-7 (15/17), 6-2, 6-4, 3-6, 7-6 (10/5)
Alex de Minaur (AUS x27) bt Henri Laaksonen (SUI) 6-4, 6-2, 6-7 (7/9), 4-6, 6-3
Rafael Nadal (ESP x2) bt Matthew Ebden (AUS) 6-3, 6-2, 6-2
Women's singles
Second round
Sloane Stephens (USA x5) bt Timea Babos (HUN) 6-3, 6-1
Petra Martic (CRO x31) bt Marketa Vondrousova (CZE) 6-4, 7-5
Aliaksandra Sasnovich (BLR) bt Anett Kontaveit (EST x20) 6-3, 6-3
Caroline Garcia (FRA x19) bt Zoe Hives (AUS) 6-3, 6-3
Ashleigh Barty (AUS x15) bt Wang Yafan (CHN) 6-2, 6-3
Anastasia Pavlyuchenkova (RUS) bt Kiki Bertens (NED x9) 3-6, 6-3, 6-3
Amanda Anisimova (USA) bt Lesya Tsurenko (UKR x24) 6-0, 6-2
Maria Sakkari (GRE) bt Astra Sharma (AUS) 6-1, 6-4
Danielle Collins (USA) bt Sachia Vickery (USA) 6-3, 7-5
Caroline Wozniacki (DEN x3) bt Johanna Larsson (SWE) 6-1, 6-3
Kimberly Birrell (AUS) bt Donna Vekic (CRO x29) 6-4, 4-6, 6-1
Petra Kvitova (CZE x8) bt Irina Begu (ROU) 6-1, 6-3
Belinda Bencic (SUI) bt Yulia Putintseva (KAZ) 7-5, 4-6, 6-2
Aryna Sabalenka (BLR x11) bt Katie Boulter (GBR) 6-3, 6-4
Angelique Kerber (GER x2) bt Beatriz Haddad Maia (BRA) 6-2, 6-3