HAYWARD -- The Arroyo High softball team picked the right time to record its biggest win of the season.

The Dons used timely hitting and a gutsy pitching performance from a junior varsity call-up to knock off top-seed Castro Valley 6-3 in the finals of the West Alameda County Conference-Foothill Division playoffs at Larry Standley Field.

With the win the Dons (17-7) earn the automatic berth to the North Coast Section playoffs, which begin next week.

Arroyo starting pitcher Jen Thompson pitched went the first four innings before giving way to newcomer Natalie Matheny, who kept the potent Trojans (17-8) at bay and allowed three hits in the final three innings.

The Dons scored a run in the first before scoring two more in the third to take a 3-0 lead.

"We lost 11-0 the last time we played them so jumping out early on them gave us some huge momentum," Arroyo first-year coach Jeff Van Slyke said.

Tracy Shaw and Allison Decker both had RBI singles in the fourth to pull Castro Valley within 3-2. The Dons scored two more in the sixth when Shayne Buac singled and scored a run and Thompson drove in another run with a fielders choice.

Thompson went 2 for 4 with three RBIs and Reiley Ramos was 2 for 4 with a pair of runs scored for Arroyo. Leilani Huey went 2 for 2 for the Trojans.

WACC-Foothill playoffs Championship Arroyo 6, Castro Valley 3

Arroyo 102 002 1-- 6 11 1

Castro Valley 000 200 1-- 3 7 3

Thompson, Matheny (5) and Valdovino; Huey and Guzman. W: Thompson. L: Huey. S: Matheny. 2B: Tomkowiak (CV), Huey (CV). 3B: Thompson (A). Records: Arroyo 17-7, Castro Valley 17-8. Highlights: A -- Thompson 4 IP, 4 H, 2 R, ER, 2 for 4, 3 RBIs; R. Ramos 2 for 4, 2 R; CV -- Huey 7 IP, 2 ER, 4 K, 2 for 2; Shaw 1 for 3, RBI.