Lopez, a junior, made nine saves in the first half. The Nitros, who finished tied for second with Pasadena in the Pacific League behind third-seeded Crescenta Valley, built a 5-0 halftime advantage.
"In the beginning of the game, I was super nervous," Lopez said. "I have to be there for my team because I know they will be there for me.
"I'm there for a reason. I made a lot of saves in the first half and then we scored some goals."
The Nitros received two goals apiece from Kristina Terzyan and Milene Minassians and one from Arpineh Ohanian to eliminate La Sierra, which finished 15-10.
Terzyan, Ohanian and Garcia-Solano scored one goal apiece in a little more than two minutes late in the first quarter to give the Nitros a 3-0 lead. Minassians scored twice in a three-minute span late in the second quarter to make it 5-0.
Glendale Coach Forest Holbrook said the Nitros needed a sharp effort from Lopez and a balanced scoring attack to advance.
"Every game in CIF is going to be tough," Holbrook said. "I'm certainly happy that we were able to start off with a win.
"It's always key when you can jump out early. Mariquita stepped up for us and she's one of our experienced players. She had some big blocks for us and that helped keep our momentum going."
Glendale scored three goals in less than three minutes late in the third quarter to take an 8-1 lead. Garcia-Solano had two goals and Terzyan added one in that span.