In Gee Chun equalled the lowest opening round in Women's PGA Championship history and also set the new course record at Congressional Country Club with a brilliant 64.
The two-time major winner posted the early lead at eight under par with a round which has only been achieved three previous times in the tournament, the last occasion in 2006.
Her nine birdies and one bogey set a new best mark for the recently-remodelled Blue Course in Bethesda, where Rory McIlroy won the US Open by eight shots in 2011.
In Gee Chun carded an incredible 9 birdies in the first round of the #KPMGWomensPGA@ROLEX pic.twitter.com/pe5pari3Ps
— KPMG Women's PGA Championship (@KPMGWomensPGA) June 23, 2022
"I feel so good because I always think when my name is going with something, then I feel very honoured and it makes me keep going to play golf," said In Gee.
The South Korean’s nearest challengers in the clubhouse were all seven shots back.
Stephanie Meadow saw her good start undone by a bogey and double bogey in her final four holes to finish on one over.
Meadow moved onto two under thanks to birdies on the third and fifth holes, but she bogeyed the sixth and double-bogeyed the eighth for a first-round 73.
Leona Maguire is a shot behind Meadow on two over after a birdie-free round, the Cavan native bogeying the fifth and 15th holes.
