CANONSBURG — Burying a traditional postseason rival with an offensive blitz has Seneca Valley senior midfielder Sarah Anderson and her teammates brimming with confidence.

The fourth-seeded Raiders’ girls soccer team blanked No. 13 seed Peters Township 4-0 Wednesday night in a WPIAL Class AAA quarterfinal at Big Macs Stadium.

Seneca Valley will need to recapture that magic against top-seeded and unbeaten Norwin — which is 20-0 and advanced with a 3-0 win over Plum — Monday at a site and time to be determined.

The Knights, who have only allowed four goals this season, blanked the Raiders 1-0 earlier this season.

“I think it’ll give us more confidence because we usually have problems with Peters,” Anderson said. “Knowing we can beat them and we played well together, it will give us more confidence.”

The Indians and Raiders have met eight meetings all-time in the postseason, with Seneca Valley holding a 5-3 edge.

The Raiders, who are 16-3 and the two-time WPIAL defending champions, were the first team to score more than three goals against the Indians (14-5) this season.

“I think (defeating Peters Township) prepares us well and helped us grow as a team,” sophomore midfielder Morgan Hoffman said.

Seneca Valley took a half to find its offensive bearings against Peters Township.

The Raiders, who outshot the Indians 20-12, couldn’t find the frame.

Several creative efforts from senior midfielder Megan Majeski went wide or over the crossbar.

“She’s done that all year long,” said Seneca Valley coach Dave Sylvester about Majeski’s creativity. “She’s like our point guard. We try to run everything through her. You see out here, she can move and sees the gaps.”

After halftime, everything opened up for Seneca Valley. A cross from Anderson set up the first goal.

The ball found the head of Hoffman, who headed it over Peters Township goalie Reilly McGlumphy with 37 minutes, 41 seconds remaining.

“I just knew I wanted to get something on it,” Hoffman said.

Anderson doubled the Raiders’ lead a minute later, picking up the ball on a pass from Hoffman in the middle of the field. She dribbled it toward the net, before sliding a shot past a diving McGlumphy from about 10 yards out.

Sylvester said he thought Seneca Valley would be able to exploit some gaps when the team switched sides.

He noticed Indians coach Pat Vereb was aggressive coaching his defense in the first half.

“He doesn’t have his defense and we have to get that ball back in behind this girl on the left side,” Sylvester said. “We thought she was getting tired and Sarah could get around her. We just found some gaps.”

Madeline Seibel added a goal in the 59th minute for the Raiders. Majeski added another tally in the 78th minute.

Vereb knew his team was going to be tested.

“I think overall as a team they are super athletic and work super hard,” Vereb said. “They do very well at winning balls in the air. They are an athletic team.”

The final two goals made it the most lopsided game in the postseason series. Previously, the biggest margin of victory was two goals.

Anderson hopes the Raiders can duplicate the formula to make a third straight appearance in the WPIAL finals.

“We just communicated well and the defense played well,” Anderson said. “We played our game.”