The American lost three Eagles en route to carding an 11-under-61, a new course record for La Reserva Club.
Three birdies on either side of the curve helped cement an important day for the 29-year-old, who leads into the second round of the individual competition by five shots.
“It was a great lap,” Korda told reporters. “We had a great atmosphere in the group and I was obviously very relaxed.
“I’ve never done three eagles in one round before, so I’ll definitely remember this one!”
A bogey on the eighth hole marked the only blemish on the world No. 14’s scorecard and hurt her chances of making the first under-60 finish of the tour.
“I still bogeyed and hit it into the fence, so I wouldn’t say all aspects worked,” Korda said.
“I don’t think I’ve really converted putts in the last month and since the change and the floodgates opened up today and hopefully they can continue tomorrow and that’s the beauty of golf.”
Belgium’s Manon De Roey and Slovenia’s Pia Babnik lead the chasing pack after carding six under 66.
Korda’s sister Nelly is another shot behind after shooting 67, with a double bogey on the par 5 sixth hole nullifying an eagle on the second. The world No. 3 shares fourth place with France’s Pauline Roussin.
“I played pretty well,” said Korda. “It’s my first time in Spain and I was blown away, it’s super beautiful.”
The 54-hole individual tournament runs parallel to a 36-team event, pitting a team of four – including one amateur – against each other, with the top two scores per hole counting. Each event offers a $500,000 prize pool.
Now, 10 months after Sotogrande, she is well positioned to repeat the feat after her team – made up of Finland’s Noora Komulainen, Czech Tereza Melecka and amateur Malcolm Borwick – boasted a 19-under win at half-time with a shot in the lead.
“We had a good atmosphere in the team, we kept it very easy out there,” said Korda.
“I know the girls were a little nervous at first but I told them there was no need to be nervous and that they should go out and have fun and play some golf.
“We are in Spain and the weather is nice, we are lucky to be here.”
The teams of Roussin and De Roey are a shot behind going into Friday’s decider.