TRUMBULL — Every championship caliber team faces a test in the postseason when they aren’t at top form and must find a way to survive and advance.

The St. Joseph girls soccer team — which outscored the opposition this year 85-9 in going undefeated — encountered its toughest test in the FCIAC quarterfinals against defending co-champion Staples, and needed to grind out a win to extend its perfect season.

Jenna Bike’s penalty kick with 10:47 left sent the No. 1 Cadets (17-0-0) to the FCIAC semifinals at the expense of No. 8 Staples on Friday. St. Joseph will meet Greenwich on Monday in Wilton.

Bike was tripped in the corner of the penalty area, and buried the ensuing spot kick to her left. The goal resulted in a collective sigh of relief on the St. Joseph sideline, and ensured overtime wouldn’t be necessary.

“It’s soccer,” said Cadets coach Jack Nogueira. “If we score early goals and they have to come and chase, then we could probably score two or three more. The best team doesn’t always win in soccer; I’m happy we advanced.”

St. Joseph was forced to break down a Staples defense that played nearly its entire team behind the ball and counter-attacked when the opportunity presented itself. It was a stark contrast to the 8-0 win by St. Joseph when the two teams met on the same field Sept. 26.

“Staples did a great job defending,” Nogueira said. “Give them credit, the first time we played them it was an open game, and that’s what we like.

“They defended well with 11 today.”

The Cadets exploded out of the gates and could have been 2-0 up inside the first three minutes, but Staples’ defense soon gained shape and the quality looks dissipated.

Staples had the best opportunity of the entire match, which came midway through the second half. Junior midfielder Tia Zajec robbed a Cadet defender of the ball and raced toward goal, but goalie Veronica O’Rourke got in the way and forced the shot wide.

Right after Bike’s penalty, Zajec and Lydia Shaw combined inside the box, which nearly resulted in a goal.

“Although we didn’t create a lot, we had two or three decent chances,” Staples coach Barry Beattie said. “If we score early in the second half it’s a completely different game. Our plan was to come here, set up a defensive block and make them break us down. And after 80 minutes they didn’t.”

Wreckers goalie Anna Sivinski made 11 saves, including several on shots that seemed destined for the net. Her best came early in the second half, when Marissa Grasso lofted a free kick from 50 yards out that Sivinski tipped onto the crossbar.

“(Sivinski) was top-class today, and that’s how good she can be,” Beattie said. “It’s just a matter of getting there all the time.”

Bike was able to beat Sivinski with the penalty and help avoid a repeat of last year’s penalty shootout defeat to New Canaan in the FCIAC quarterfinals.

ST. JOSEPH 1, STAPLES 0

STAPLES 0 0 — 0

ST. JOSEPH 0 1 — 1

Records: Staples 9-7-1; St. Joseph 17-0-0. Goals: SJ—Jenna Bike (PK). Goalies: Stap—Anna Sivinski (11 saves); SJ—Veronica O’Rourke (1).