The gifted allrounder Ruffels is joint-leader at 11 under par alongside a fellow tennis-lover, Englishwoman Cara Gainer, going into the last round of the fourth major of the season at the Evian Resort Club.
But just a shot behind, amid a four-way tie for third place, are two of Ruffels' Aussie colleagues, Grace Kim and Minjee Lee, who's still in a great position to gun for her fourth major title and her second in just three weeks after her Women's PGA title triumph.
In glorious weather at the picturesque course overlooking Lake Geneva, it proved a spectacular moving day for the Australian assault at a tournament where they've enjoyed considerable success, with Minjee Lee having won her first major there in 2021 and Steph Kyriacou finishing runner-up last year.
Ruffels, who had started unpromisingly with a bogey, put herself on pole position with six birdies, including a brilliant late burst of four in the last eight holes that pushed her atop the leaderboard alongside Gainer, whose 64 was the second-best round of the afternoon.
Lee, who had begun well in Thursday before a second-round struggle, reignited her challenge with a flawless 66, featuring five birdies, while Kim birdied her last hole for a one-under 70.
The pair are level with world No.2 Jeeno Thitikul and South Korea's Somi Lee at 10 under for the championship on a quality-packed leaderboard, although world No.1 Nelly Korda was out of the picture after a hugely disappointing 75 left her 10 off the pace.
World No.71 Ruffels and No.129 Gainer felt like an unlikely pair to go out last on Sunday but they have plenty in common, with both having dreamed of one day being professional tennis players and having come close to achieving their ambition.
Now, they're shooting for the biggest prize of their lives in their adopted sport.
American-born, Melbourne-raised Ruffels was once Australia's top junior player before turning her attention to golf at the age of 14, and she's carved out an ever improving career, becoming US Women's Amateur champion in 2019.
But she's never turned her back on tennis, having enjoyed a refreshing break with her boyfriend at Wimbledon as a guest of doubles great Todd Woodbridge before setting off for the French Alps.
"It was such a cool experience," Ruffels smiled. "It was great to relax and not touch the clubs for a few days and get over jet lag. Seems to have worked this week."
The 29-year-old Gainer, too, admits: "Tennis was, I guess, my first love." But she turned to golf at 14 and quickly started playing off scratch.
"I do still really enjoy it. I don't really play any more but I love to watch it. Obviously Wimbledon is on this week so that's my evening," she said, as her round finished just before Amanda Anisimova and Iga Swiatek were due to go on court for the Wimbledon Ladies' final.
Perth's world No.6 Lee could yet still be the one they have to beat s she seeks to become the first woman since Inbee Park in 2013 to capture back-to-back majors, but Kyriacou looks to be out of the hunt after a 74 left her alongside Korda at one-under.
