Provo » San Diego State's Cat Walker, the Mountain West Conference women's soccer player of the year, was mostly absent during Saturday's final. She was smothered by the combination of host BYU's defense and the South Stadium altitude.

But Walker had one clear moment of opportunity and she made the most of it. With a turn and a blast from 25 yards away, Walker's laser past Cougar keeper McKinzie Olson in the 29th minute transformed the Aztecs' afternoon into a cry of joy.

BYU could only cry, victims of a 1-0 upset. Afterward, as the teams met at midfield, SDSU coach Mike Friesen, bent over with hands on knees, could barely contain his excitement.

"Unbelievable," he said. "To come to BYU and win on this field in front of a huge home crowd [of 1,627] at elevation is amazing. Just amazing."

The victory sent the No. 2-seeded Aztecs (14-3-5) on to the NCAA College Cup for the first time in 10 years, while No. 1 seed BYU (17-3-2) must wait until Monday night to find out if and when it plays.

"We still have a lot of season ahead of us," red-eyed BYU defender Andrea Willis said. "[Walker] just had a great shot. There was nothing you could do about that."

San Diego State spent much of the second half in defense of its half of the field, absorbing wave after wave of Cougar attackers. SDSU goalie Aubree Southwick made six saves and was also lucky as BYU, which took 17 shots, simply missed point-blank opportunities.

"Sometimes balls fall for you, sometimes they don't," BYU coach Jennifer Rockwood said. "We won 17 games and had an outstanding schedule. I believe we deserve a chance to be in the tournament and keep our winning season alive."

Despite two yellow cards, including one on BYU's Jennie Marshall for arguing with the official, the game was without incident. Rockwood said the Cougars, coming off a rough outing with New Mexico, were focused.

"The energy was there, the excitement was there," she said.

Save for Walker's effort, the finishing wasn't.

martyr@sltrib.com