The Associated Press Jessica Pegula waves after ousting Oksana Selekhmeteva early Saturday.

MELBOURNE, Australia — Play was suspended on outside courts and briefly halted on undercover arenas in the mid-afternoon Saturday under the extreme heat rules at the Australian Open.

Defending champion Jannik Sinner was down a break in the third set of his third-round match against Eliot Spizzirri and struggling with cramping when play was stopped for several minutes to allow the roof on Rod Laver Arena to be closed.

A match on John Cain Arena was also suspended while the stadium roof was closed. All matches on outside courts were stopped when the tournament’s heat index hit 5 and were expected to be on hold for at least three hours.

The temperature was around 35 degrees Celsius (95 Fahrenheit) when the extreme heat policy was invoked, and the forecast is for searing temperatures up to 40 degrees Celsius (104 Fahrenheit).

An earlier start than usual on Day 7 and hot weather were no worries for defending champion Madison Keys and her fellow American Jessica Pegula in their morning matches. The ninth-seeded Keys beat Karolina Pliskova 6-3, 6-3 in the opening match on Rod Laver Arena on Saturday, while sixth-seeded Pegula defeated Oksana Selekhmeteva 6-3, 6-2 in the first match at Margaret Court Arena.

Next up for the two Americans is a fourth-round encounter against each other.

“I served well, and overall I give myself a full pat on the back for that,” Keys said of her win. “It gives yourself a boost when you can find your best tennis, trust your game and try to do the right things.”

Pegula said she didn’t mind the hotter temperatures — “being a Floridian I was ready for it.”

Keys said she expects a tough match against Pegula in the fourth round.

“Jess is such a great player, consistently doing well in every match she plays,” Keys said. “She is in every single match. It also makes it hard being friends.”

There was an all-American encounter on Saturday as well — fourth-seeded Amanda Anisimova beat Peyton Stearns 6-1, 6-4 to advance to the Round of 16.

Alcaraz tested

Carlos Alcaraz had to acknowledge that while he won the third-round match, he lost the battle of the drop shots against Corentin Moutet.

That could be a first for the 22-year-old Spaniard, who grew up relentlessly practicing his drop shots and is now at the Australian Open chasing a career Grand Slam.

The left-handed Moutet mixed things up for Alcaraz in an almost festival Friday vibe on Rod Laver Arena, his blend of drop shots, slice, lobs, tweeners, volleys and even an underarm serve keeping the world’s No. 1-ranked player on his toes.

“When you play someone like Corentin you don’t know what’s going to be next,” Alcaraz said after his 6-2, 6-4, 6-1 win over the No. 32 seed. “I had so much fun on the court. As you could see, we both pulled off great shots. Great points.”