The Spartans (14-5-5), who won a Rio Hondo League championship, will take on the winner of Santiago-Mountain View game at 3 p.m. Tuesday at a site to be determined.
La Cañada Coach Alex Harrison said he was pleased at the way his squad was able to step up in the light of adversity it faced.
"We are already a very young team," said Harrison, who inherited a team that graduated nine seniors last season, a number who are playing Division I soccer. "We had only three seniors starting today. But I thought they did a good job and they came out to play."
The Spartans received a solid performance from junior striker Armand Bagramyan, who had a goal and assisted on a second.
Bagramyan said it was imperative that La Cañada get out to a good start to open the playoffs.
"I think this just sets the tone for the whole tournament," he said. "If you get a win for the first time and you get a solid win, hopefully that momentum will carry on to the next game."
La Cañada came out in the opening minutes and dictated play against Wilson (11-10-1), which finished fourth in the Valle Vista League. Through the first 15 minutes, the Spartans defense didn't allow the Wildcats a shot.
Although the Spartans had their share of scoring chances in the first 30 minutes, they couldn't find the back of the net. That changed in the 31st minute when Marc Kaesler scored on an assist from Bagramyan.
La Cañada came back nine minutes later to take a 2-0 advantage, as Jeff Becker scored on a blocked shot by Carlos Ruano.
"I told the guys the first 15 or 20 minutes is going to be crucial to see how we respond and how we were going to play," Harrison said. "I think the guys did well. They were basically pressing the whole first half."
The Spartans had 13 shots in the first half.
La Cañada made it 3-0 in the 61 minute when Bagramyan got a pass from Noah Duncan, and with his back to the goal, turned slightly and rifled a shot into the lower left corner of the net.
"I thought we filled in the positions pretty good," Bagramyan said of players who filled in for the missing Spartans. "We have the players who can step up"