By winning, the fourth-seeded Spartans move to a quarterfinal matchup Thursday against fifth seed New Hope-Solebury, a 2-0 winner Tuesday over Delaware County Christian.
Springfield improved to 11-2 overall, the losses coming in nonleague games against Upper Dublin, 2-0, and Plymouth Whitemarsh, 2-1.
Dock finished the season a disappointing 7-10.
Springfield was led by sophomore Juli Cardamone, who scored two goals but acknowledged she was a little slow in getting started.
Her ninth and 10th goals of the season were the last two scored Tuesday by the Spartans.
"I think it was a case of nerves," Cardamone said about not only her start but also her teammates' start. "We weren't communicating very well at all. We finally put it together in the second half.
"Even though we didn't score in the first half, I was confident we'd come out with a win."
Junior Libby Field got the Spartans the only goal they would need when she connected with 7 minutes, 50 seconds gone in the second half. The goal came on a perfectly executed offensive penalty corner.
Maureen Leis made it 2-0 a little more than minute later.
Cardamone's first goal five minutes later completed the Spartans' flurry. She added her second with 4:20 to play.
"When we played them the first time [during the league season], it was under the lights and on turf," said Nixon, whose team plays on grass. "They scored in the first 1:16, and we had to come back. It was a good game."
Nixon, who has been coaching since 1967, said she's seeing steady improvement in her relatively young team with each game. The Spartans lost two 20-goal scorers from last season's team.
Dock coach Shannon McCracken was obviously disappointed by the loss.
"We lost to them 2-1 [earlier]. I think we showed that we're capable of playing with them," she said. "I thought we played well today. We just didn't score."
Christopher Dock 0 0 – 0
Springfield (M) 0 4 – 4
Goals: S-Juli Cardamone 2, Libby Field, Maureen Leis.
Saves: CD-Monica Roth 5; S-Kim Machalette 2.
Contact staff writer Don Beideman at 267-815-0733 or dbeideman@phillynews.com.