KENNEBUNK — It got tense in the sixth inning. And worrisome, because Kenebunk’s senior leader, Maddie Pike, injured her knee on a fluke play.

But the youthful, third-seeded Rams, and freshman pitcher Julia Pike in particular, recovered in time to beat No. 6 Portland, 5-4, in a Class A South softball quarterfinal Wednesday.

After allowing four runs on four hits, two walks and two poor-decision outfield throwing errors in the sixth inning, Pike retired Portland in order in the seventh, recording her 12th and 13th strikeouts.

“I was kind of like frustrated with (the injury) because that’s one of my players being down, but Melody (Rouselle) stepped in there at third and did a great job,” Pike said of her sister’s injury. “I knew I needed to have confidence throughout, so I just bared down and threw the next pitch.”

Kennebunk (15-2) advances to the semifinals Saturday against the winner of Thursday’s game between No. 10 South Portland and No. 2 Biddeford. The semifinal will be played at the home of the higher seed.

No. 6 Portland finishes 11-6.

“They’re a really good team. They deserve to win. They played really clean ball,” said Portland pitcher Sadie Armstrong. “But it was a battle to the end, so it made it a lot more fun, a little easier to take.”

Pike was dealing early, featuring a lively fastball. She retired the first nine hitters, eight by strikeout.

Maddie Pike hit an RBI single in the first inning and Isabella Real and Emily Hutchins had RBI singles in the second.

The Rams tacked on single runs in the fourth and fifth on RBI grounders by Real and Sky Holder.

Portland began to make more contact its second time through the order. Hannah Hawkes and Gabby Daniels (double) had solid line-drive hits, but through five innings, Kennebunk led 5-0 and was in clear control.

In the sixth, Portland’s Jordan King drew a leadoff walk – the first allowed by Pike – and moved to second on a sacrifice bunt. Then the trouble started.

Hawkes flew out to left for the second out, but the throw back to the infield sailed over third base. Maddie Pike backpedaled to try to get the throw and fell awkwardly, injuring her knee. King scored when the throw went out of play.

Hadleigh McPartlan, Armstrong and Halle Chase followed with sharp singles. Another two-base throwing error after Chase’s hit – by reserve outfielder Andrea Collin, who went to right when Rouselle took over at third – made it 5-3. Daniels drove in a fourth run with her second hit before Julia Pike shut down the inning with a strikeout.

“We just kind of powered through it,” said Real, Kennebunk’s shortstop. “We just talked about it as a team, kept our heads. We felt confident in (Julia) throwing it and just finishing up the game.”

A year ago, Kennebunk was so short on players it received a waiver from the MPA to allow eighth-graders to play. Now freshmen, players like Julia Pike, Holder (first base), Rouselle, Talia Kellum (second base) and Katie and Emma Orendorf are difference makers.

“They’re making regular contributions for us and it’s really fun to see,” said Kennebunk Coach Eddie Pike.