Kim Parker had 16 points and BYU scored 20 straight in the second half to rout No. 19 Gonzaga 70-40 on Thursday night, handing the Bulldogs their worst conference loss in a decade.

"Unfortunately we couldn't get (the 20-0 run) stopped once it got started," Gonzaga coach Kelly Graves said. "We were completely outplayed."

Jennifer Hamson added 14 points and Kristen Riley had 11 points and 10 rebounds for the Lady Cougars (22-4, 10-2 West Coast). Haley Steed had eight points and 10 assists to move into fourth all-time on the school's career assist list.

Kayla Standish scored 12 points to lead Gonzaga (21-4, 10-2). The Bulldogs leading scorer missed her first 10 shots. Gonzaga shot only 15 percent from the floor in the first half and finished the game making only 22 percent. The Bulldogs went eight minutes without a point in the second half and scored only nine points over the final 13:47.

"I don't know how many shots we missed early at the rim, but maybe if we make a few of those things might have turned out different," Graves said.

Gonzaga was last beaten this bad by Santa Clara on Jan. 10, 2002, losing 99-69.

The Lady Cougars, now tied with Gonzaga atop the West Coast standings, shot 65 percent in the second half and 45 percent for the game.

"It was our night," BYU coach Jeff Judkins said. "Some nights you have those; the ball bounces your way."

With both teams struggling to make shots in the opening half neither team could get much separation until Riley hit the game's first 3 and Dani Peterson followed up with a hook to put BYU ahead by seven.

Gonzaga made only 5 of 33 shots in the first half, while BYU wasn't much better hitting only 8 of 28. The two teams were a combined 2 of 16 from 3-point range in the opening 20 minutes.

"I think tonight was one of the best defensive efforts I've coached in a long, long time. We were physical. We executed the game plan very well . . . I think we did a good job of not letting them get easy baskets," Judkins said.

The Bulldogs, by adding some backcourt pressure, trimmed the margin to 34-31 early in the second half on a steal and layup by Haiden Palmer.

But BYU took over from there and scored 20 straight. Stephanie Vermunt came off the bench to hit two 3s and score eight in the stretch. Hamson had seven during the run.

Gonzaga struggled with BYU's length inside, especially the defensive prowess of 6-foot-7 Hamson, who finished with three blocks.

In Gonzaga's 27-point win over BYU last season, Standish, Katelan Redmon and Kelly Bowen combined for 56 points. In Thursday's loss the trio scored only 25 and made only 9 of 35 shots.