England's Mimi Rhodes shot an opening six-under-par 66 to take a two-shot lead in the Aramco Houston Championship.
Rhodes, chasing a fourth win in her rookie season on the Ladies European Tour, fired seven birdies - including three in a row from the 13th - despite suffering from blisters on her feet.
"It really helps playing with pain because it distracts you from everything," said Rhodes, who leads the LET order of merit.
"The heat was tough to handle, but I was drinking water every hole. I was just playing my game out there and trying not to get heatstroke.
"My feet get really sweaty in the heat, it's more of a sweat rash than blisters. It's a good distraction."
Spanish duo Nuria Iturrioz and Luna Sobron Galmes, Malaysia's Ashley Lau and Anne Van Dam of the Netherlands are two shots back in the 54-hole competition, which also features a team event over the first two rounds.
Charley Hull, who won the event in 2021 and finished second last year, is among a group a shot further back which also includes fellow English players Cara Gainer, Amy Taylor and Megan Dennis.
France's Celine Boutier headed the leading team after opening with a two-under-par 70.
It was a tough start for the trio of Irishwomen in the field.
Lauren Walsh is three-over after an opening 75, one ahead of Annabel Wilson. Sara Byrne is a further two shots back on six-over-par having carded a 78.
