One event. One win. One American record.

The Stanford women’s swimming and diving team opened the Pac-12 Championships with a record-setting 200-yard medley relay Wednesday night at Weyerhaeuser King County Aquatic Center near Seattle.

Sacred Heart Prep-Atherton grad Ally Howe (backstroke; 23.62), Sarah Haase (breaststroke; 26.20), Janet Hu (butterfly; 22.82) and Lia Neal (freestyle; 21.51) combined to finish the 200 medley relay in 1:34.15 — the fastest finish in American history. It surpassed a 4-year-old record set by Cal at the 2012 NCAA Championships.

Diving also started on the first day as Stanford senior Alex Clay finished as the Pac-12 runner-up in the 1-meter with a score of 297.05 and Gracia Leydon-Mahoney was fourth at 293.55.

“I’m really proud of the team’s performance today,” said fourth-year head coach Greg Meehan. “Our divers got us on a good roll this afternoon, and then we had a great relay session tonight. More important than the (American) record, I’m proud of how everyone swam. Specifically, Nicole Stafford leading off our 800 free relay in a time that will qualify her for NCAAs for the first time as a junior was a really meaningful moment.”

Pac-12 Networks will broadcast the first two days of action on tape delay today. Day 3 can be seen on Saturday and the final day will air Sunday. Each broadcast will begin at 10 a.m.