The defending champion Lancers improve to 14-5-2 overall with the win and advance to Thursday's semifinals at 2 p.m. (PST) against the winner of Union (Tenn.) and Grace (Ind.).
Roberts Wesleyan falls to 10-9-1 and into the consolation bracket.
The Lancers wasted little time getting on the board, scoring three times in the first 27 minutes.
"I thought we started well and had some purpose and identity with what we were trying to do," said CBU Head Coach Ryan Jorden. "When you score early, it makes the game a lot easier."
Four different Lancers scored. Alex Anderson and Marc Hope each had a goal and an assist. Cole Schmit had two assists. Joey Pacheco and Ian Clark both made two saves as the Lancers got their ninth shutout of the year, one shy of tying the program's single season record set in 2010 and again last year.
Jonathan Fausto started the barrage with a strike in the 10th minute. Schmit set up for a free kick just outside the area and slid a ball on the floor to the left of the wall. Fausto ran onto it and hammered home the game's first goal right into the center of the net.
Just seven minutes later, Anderson took a through ball from Hope on the right side and easily tucked away his team-leading seventh goal of the year.
Hope then made it 3-0 in the 27th minute, ripping a ball to the upper 90 and the Lancers carried a three-goal advantage into halftime.
Twenty-three different Lancers played. Eleven of them took at least one shot. The Lancers outshot Roberts Wesleyan 18-10, including an 11-4 advantage on goal.
"We had guys come on and give good performances," said Jorden. "I was happy with the entire group. Everyone contributed."