Melbourne - Former US Open champion Juan Martin Del Potro fought off rising Russian Karen Khachanov as he battled through the pain barrier to reach the third round at the Australian Open on Thursday.
The Argentine 12th seed needed 3 hours and 45 minutes in oppressive court conditions to see off the 47th-ranked youngster 6-4, 7-6 (7/4), 6-7 (0/7), 6-4 on Hisense Arena.
Del Potro, 29, in his first appearance in Melbourne for four years after wrist injuries, will face Czech veteran Tomas Berdych in the third round.
"It was really difficult to play. Almost 40 (Celsius) degrees out there is too much for the health," Del Potro said.
"We did a big effort to play good tennis. The weather condition was too high for playing tennis.
"I survive. I will play after tomorrow I hope in different conditions.
"I have pain everywhere after that match but I am still standing up and that's good," he added.
Del Potro, who reached the third round in Melbourne for the fifth time, is looking to improve in his quarter-final appearances in 2009 and 2012, losing to Roger Federer both times.
The Argentine, who upset Federer in the 2009 US Open final, came into Melbourne a losing finalist to Roberto Bautista Agut in Auckland this month.
Results from the Australian Open on Thursday:
Men's singles
2nd round
Albert Ramos (ESP x21) bt Tim Smyczek (USA) 6-4, 6-2, 7-6 (7/2)
Marton Fucsovics (HUN) bt Sam Querrey (USA x13) 6-4, 7-6 (8/6), 4-6, 6-2
Nicolas Kicker (ARG) bt Lukas Lacko (SVK) 6-2, 7-5, 1-6, 7-5
Dominic Thiem (AUT x5) bt Denis Kudla (USA) 6-7 (6/8), 3-6, 6-3, 6-2, 6-3
Tomas Berdych (CZE x19) bt Guillermo Garcia-Lopez (ESP) 6-3, 2-6, 6-2, 6-3
Fabio Fognini (ITA x25) bt Evgeny Donskoy (RUS) 2-6, 6-3, 6-4, 6-1
Adrian Mannarino (FRA x26) bt Jiri Vesely (CZE) 6-3, 7-6 (7/4), 5-7, 6-3
Novak Djokovic (SRB x14) bt Gael Monfils (FRA) 4-6, 6-3, 6-1, 6-3
Chung Hye-On (KOR) bt Daniil Medvedev (RUS) 7-6 (7/4), 6-1, 6-1
Julien Benneteau (FRA) bt David Goffin (BEL x7) 1-6, 7-6 (7/5), 6-1, 7-6 (7/4)
Juan Martin Del Potro (ARG x12) bt Karen Khachanov (RUS) 6-4, 7-6 (7/4), 6-7 (0/7), 6-4
Women's singles
2nd round
Bernarda Pera (USA) bt Johanna Konta (GBR x9) 6-4, 7-5
Barbora Zahlavova Strycova (CZE x20) bt Lara Arruabarrena (ESP) 6-3, 6-4
Maria Sharapova (RUS) bt Anastasija Sevastova (LAT x14) 6-1, 7-6 (7/4)
Agnieszka Radwanska (POL x26) bt Lesya Tsurenko (UKR) 2-6, 7-5, 6-3
Caroline Garcia (FRA x8) bt Marketa Vondrousova (CZE) 6-7 (3/7), 6-2, 8-6
Lauren Davis (USA) bt Andrea Petkovic (GER) 4-6, 6-0, 6-0
Lucie Safarova (CZE x29) bt Sorana Cirstea (ROM) 6-2, 6-4
Karolina Pliskova (CZE x6) bt Beatriz Haddad Maia (BRA) 6-1, 6-1
Hsieh Su-wei (TPE) bt Garbine Muguruza (ESP x3) 7-6 (7/1), 6-4
Aliaksandra Sasnovich (BLR) bt Mirjana Lucic-Baroni (CRO x28) 6-3, 6-1
Angelique Kerber (GER x21) bt Donna Vekic (CRO) 6-4, 6-1
Ana Bogdan (ROM) bt Yulia Putintseva (KAZ) 1-6, 6-2, 6-3
Naomi Osaka (JPN) bt Elena Vesnina (RUS x16) 7-6 (7/4), 6-2
Madison Keys (USA x17) bt Ekaterina Alexandrova (RUS) 6-0, 6-1