Keys sweating on Mertens test in Open Round 3

Melbourne - American Madison Keys prevailed in humid conditions on Thursday to set up a testing Australian Open third round challenge against Belgium's Elise Mertens.

Both players are past semi-finalists at Melbourne Park and hungry for more success at the season-opening Grand Slam.

"That's a tough match. We've played once before and it was really tough," 17th seed Keys said after a 6-3, 6-4 second round win over Russia's Anastasia Potapova.

Keys beat Mertens, who is seeded 12th at this year's tournament, in their only previous meeting in the first round of the 2017 US Open, when the American progressed to the final.

She lost the decider to Sloane Stephens but has gone on to become one of the most consistent performers at Grand Slams, reaching the semis at the French and US Opens last year, as well as the quarter-finals in Melbourne.

The 23-year-old reached the final four in Australia in 2015, while Mertens managed the feat last year.

Keys said she was pleased to dispose of Potapova in straight sets in draining conditions, minimising her time on court ahead of the Mertens match.

"It's really humid out here, my shirt's soaking wet, so I'm glad I got it done it two sets today," she said.

"I just go out and I do my best and it's always great when you have amazing support behind you."

Results from Day 4 of the Australian Open on Thursday:

Men

Round 2

Kei Nishikori (JPN x8) bt Ivo Karlovic (CRO) 6-3, 7-6 (8/6), 5-7, 5-7, 7-6 (10/7)

Women

Round 2

Camila Giorgi (ITA x27) bt Iga Swiatek (POL) 6-2, 6-0

Wang Qiang (CHN x21) bt Aleksandra Krunic (SRB) 6-2, 6-3

Elina Svitolina (UKR x6) bt Viktoria Kuzmova (SVK) 6-4, 6-1

Karolina Pliskova (CZE x7) bt Madison Brengle (USA) 4-6, 6-1, 6-0

Anastasija Sevastova (LAT x13) bt Bianca Andreescu (CAN) 6-3, 3-6, 6-2

Elise Mertens (BEL x12) bt Margarita Gasparyan (RUS) 6-1, 7-5

Hsieh Su-wei (TPE x28) bt Laura Siegemund (GER) 6-3, 6-4

Madison Keys (USA x17) bt Anastasia Potapova (RUS) 6-3, 6-4