South Korea's Eun-Hee Ji didn't lose a hole on Saturday, defeating Madelene Sagstrom of Sweden 7 and 6 in the quarterfinals of the LPGA Match-Play event in Las Vegas.

The match ended after the 12th hole at Shadow Creek Golf Course. Ji didn't realize the match was over until her caddie told her.

"I didn't know that was my last hole, so I was thinking like, 'Oh, I really tired like from now, and then, OK, I need more focus because I want to get quicker," Ji said.

Every other quarterfinals match was decided in a playoff.

Lilia Vu beat Jenny Shin of South Korea 1 up on the second playoff hole, Japan's Ayaka Furue defeated Jodi Ewart Shadoff on the fourth playoff hole, and Andrea Lee needed two playoff holes to dispatch upstart Gemma Dryburgh.

The 64-player field was divided into 16 groups of four in a round-robin group stage that ended Friday. The group winners advanced to a 16-player, single-elimination bracket. The eight players in the quarters advanced from the knockout stage earlier in the day.

Ji will play Lee in Sunday's semis while Furue draws Vu.

Furue said she was more mentally drained than physically.

"Coming into the back nine, I was 4-down and so it was pretty mentally draining having to rely on trying to get some birdies and give myself enough opportunities get those birdies, so I would say that's why it's so mentally draining," Furue said.

Lee ended the Cinderella run of Dryburgh, who gained entry into the field Tuesday night. Dryburgh bolted to a 3-up lead and led 2-up at the turn.

"You can't really expect your opponent make mistakes. You've got to tell yourself that you need to be the one to make the birdies and the putts," said Lee. "That's what we both did coming down the stretch."