LAS VEGAS – Haylee Andrews scored on a floater in the lane with 3.6 seconds left and fourth-seeded Portland, which trailed by 20 points in the first quarter, upset top-seeded and 11th-ranked Gonzaga 70-69 on Monday in the semifinals of the West Coast Conference tournament.

Gonzaga, which trailed by six when WCC player of the year Jill Townsend fouled out with 5:13 to play, took the lead on a layup by Jenn Wirth — who contributed 21 points and eight rebounds — with 8.6 seconds to go.

After a timeout, Andrews took the ball near the top of the key, drove left and stepped through the defense toward the basket, putting up a short right-handed shot for the winning points.

A rushed three-point try by Gonzaga’s Jessie Loera from beyond the top of the key wasn’t close as time expired.

Freshman Alex Fowler scored 22 points and grabbed nine rebounds for Portland (20-11), which was picked last in the WCC preseason poll. Kate Andersen added 18 points and Andrews had 16 on her 20th birthday.

The Pilots, last in the championship game in 1997, will face second-seeded San Diego for the title. San Diego beat Pepperdine 59-44 in the other semifinal game.

Gonzaga (28-3) made 13 of its first 14 shots and led 29-9 late in the first quarter but Portland was back in the game by halftime, trailing 39-35.

The Pilots were up 53-51 entering the fourth.

“Anyone can beat anybody on any given night, so you have to do your best every single night,” said Townsend, who scored 15 points. “Unfortunately, it wasn’t our best tonight.”

Zags coach Lisa Fortier said, “It’s hard; I’m not very good this year at postgame- loss speeches, which is probably a good thing. This one in particular, there were a lot of tears, of course.”