Steph Kyriacou has the chance to win the first major title of her soaring career - but the Sydneysider is determined to sleep easily as she enters the last round of the Evian Championship leading by a shot.

The 23-year-old from Coogee has edged one stroke clear of Japan's Ayaka Furue and American Lauren Coughlin in the season's fourth major, and has the chance to emulate her compatriot Minjee Lee, who won on the Evian Resort course three years ago.

Kyriacou hasn't put a foot wrong so far in the French event, firing a four-under par 67 in the hot conditions on Saturday for a 54-hole, 14 under par total of 199.

The world No.100 had a long day, having also had to finish off her second round from 8am following Friday's storm. She completed it for a second-straight 66, lying second overall, and then disappeared for a quick nap before teeing off five hours later.

Starting her third round two strokes behind playing partner Furue, the Sydneysider enjoyed a fine back nine in their last-group duel to edge into the lead.

And after sinking a tough downhill seven-footer for birdie on the last to be the outright leader, she smiled: "I'm very excited to sleep. I can say that.

"Yeah, it was a great day. Definitely a long day, but lots of good things happened. Good momentum into tomorrow, so after a good sleep, I think I'll be ready.

"Same as the last three days, one shot at a time, try not to get ahead of myself. I know I'm in the lead, so that's nice. Being in contention on Sunday, I don't think I've been in contention in a major before, so it's exciting.

"Obviously I want to win; so do the other girls. But I think for myself personally, when I like want something too much, I start to try and force things, so I'm probably going to stay back a bit from that.

"That seems to work for me. I'm very chatty on the course and stuff, so just staying like how I play my best and not trying to do things just because of the situation I'm in."

The challenges will come thick and fast on the final day, with Furue, who wasn't happy with her third-round 70, on Kyriacou's tail, along with Coughlin, who holed from 25 feet for an eagle on the ninth and 18 feet for another on the 18th in her 65.

Thailand's Pajaree Anannarukarn is another three strokes back on 10 under.

Kyriacou's roller-coaster third round, which featured seven birdies and three bogeys, now gives the two-time Ladies European Tour winner a fine chance of surpassing her best-ever finish at a major, her joint-seventh place at the British Open two years ago.

Three other contenders are five shots back at nine under - American Ally Ewing, who shot a 64 on Saturday, South Korea's Hye-Jin Choi (71) and Patty Tavatanakit of Thailand, whose 72 dropped her from second place to a seventh-place tie.

Australia's former champion Lee shot a third-round 68 which was ruined by a double-bogey six at the 11th. She's tied for 19th on six under.

Hannah Green was on one under after a 70, with Grace Kim one over following a 74 and Gabriela Ruffels four over (76).