Rianne Malixi got rid of American Ellie Koo with a birdie and an early run of pars, coming away with a 5&3 victory in the Round of 64 of the US Women's Amateur Match Play at the Bel-Air Country Club in Los Angeles, California Wednesday.

It was one of the few lopsided results in the first day of head-to-head duels that saw six matches go to extra holes, the most in a US Women's Amateur since 2016 with top seed Briana Chacon surviving Olivia Duan on the 19th hole, breaking a sort of a medalist curse where six of the last nine No. 1 seeds have fallen to their No. 64 seeded rivals.

Malixi, who moved into the knockout phase at No. 23 after finishing tied at 18th in the 36-hole stroke play qualifying, pounced on Koo's miscue on the par-4 No. 2 to seize control, birdied No. 4 and won the next two holes on her opponent's mistakes to go 4-up.

Although she failed to match Koo's birdie on the par-5 eighth after hitting two bunkers on her way to the green, the ICTSI-backed shotmaker birdied Nos. 10 and 11 to pull away by five holes.

She yielded the 12th on a bogey, regained the hole on next the with a par, lost No. 14 on another mishap but wrapped it up despite a bogey on No. 15 as Koo holed out with a double-bogey.

Malixi, runner-up in last month's US Girls' Junior in Colorado, faces American Bailey Shoemaker at 8:50 a.m. in the Round of 32 Thursday with the winner slugging it out with the victor in the Hailey Borja-Sara Im clash in the Last 16 in the afternoon expected to likewise test the surviving field's staying power.

No. 63 Charlotte Cantonis, meanwhile, produced the biggest result when she stunned second seed Andrea Lignell from Sweden, 4&3, No. 54 Aussie Caitlin Peirce pulled off a 1-up win over No. 11 Savannah Grewal of Canada, and No. 53 Thienna Huynh shocked recent US Girls' Junior winner Kiara Romero, 6&5.

A slew of fancied bets, however, advanced with Anna Davis scoring a 3&2 win over Amanda Sambach; Gianna Clemente crushed 2021 champion Jensen Castle, 4&3; last week's Canadian Amateur champion Lauren Kim routed Brianna Navarrosa, 5&4; Yana Wilson dispatched Ellie Szeryk, 6&4; Rachel Kuehn held off Kaleiya Romero, 2&1; Rachel Heck outlasted Sera Hasegawa on the 21st hole; and Rin Yoshida gaining with a walkover win over Lauren Miller, who withdrew due to illness.