The Lions got to La Ca"ada starting pitcher Kelson Brown (3-1) with a solo home run in the second by Nick Kimball and a solo home run in the third by Brent Keys that landed on the freeway before rolling to the center median.
La Ca"ada Coach Dennis Ballard, whose team saw its winning streak snapped at nine, said the Lions are perfectly suited for their field.
"You walk in this park and we found out that they have some good hitters," said Ballard, whose team opened the playoffs Thursday with a 5-0 home victory against Serra. "It's a field that's tailor-made for that team.
"We let the game get out of hand early. Kelson was a little flat out there. He served up a couple of shots."
Brown turned in a fine effort against Serra, allowing one hit in six innings. After escaping a first-inning jam, Oaks Christian got to the senior right-hander.
Kimball's home run off a protective netting gave the Lions a 1-0 lead.
Then Kimball and Casey Lee had run-scoring singles against Brown ? who will attend Linfield College in Oregon in the fall ? to extend the lead to 5-0.
The Spartans couldn't muster any offense against Oaks Christian starting pitcher Tommy Grillo (6-1) through three innings. The right-hander retired the first 10 batters and didn't allow a hit until the fourth, when the Spartans scored twice.
Oaks Christian scored six runs in the fifth against Brown and reliever Kevin Thompson. Brown allowed eight runs ? all earned ? and nine hits in 4 1/3 innings.
La Ca"ada scored two runs in the sixth.
Ballard said he stood in the third-base coaching box in the seventh, reflecting on how the Spartans went from being a .500 squad to a playoff team in nearly six weeks. The Spartans, who began the season 5-5 before winning nine in a row, placed second in the Rio Hondo League behind Monrovia.
"We fought back and put on quite a show," said Ballard, who led the Spartans to the league championship in 2005. "In the last inning, I was thinking about our whole season and how we won nine in a row.
"It was a great experience for us to go through that nine-game winning streak."
Stanley Kim and Brown scored two runs each.
Keys had three hits and drove in three runs for Oaks Christian, which got two hits each from Kimball and Lee.
The Lions, who opened the postseason with a 3-1 victory against visiting Carpinteria on Thursday, finished with 11 hits. They will next meet Serrano in a quarterfinal game Friday.