Zylstra, starting in place of an injured Noah Hartsock, jump started the Cougars, scoring their first seven points and 10 in the first half, to stake BYU to an early lead.
In the end, BYU defeated San Diego, 73-68, in the West Coast Conference quarterfinals.
Hartsock ended up with a game-high 19 points while Zylstra had 12.
TRENDS: Over the past decade, every No. 3 seed has advanced to the semifinals of the WCC Tournament. With the Cougars' victory Friday, the No. 3 seed is now 10-0.
The bad news for BYU?
The No. 3 seed is just 1-8 in the semifinals during that span.
BYU AT THE ORLEANS: The Cougars are now 4-1 all-time at the Orleans Arena. In November 2007, BYU played a pair of top 10 teams here in the Las Vegas Invitational. BYU defeated No. 6 Louisville, 78-76, then fell to No. 1 North Carolina, 73-63. In 2009, the Cougars defeated Nevada, 110-104, then whipped Nebraska, 88-66, in the Las Vegas Classic.
NOTES: Former BYU star and Boston Celtics general manager Danny Ainge was in attendance Friday. … Friday's game was scheduled to tip off at 9 p.m. MST, but it didn't start until 9:48, 30 minutes after the conclusion of the other quarterfinal game, San Francisco's win over Loyola Marymount.