LAKEWOOD — Tension began building in the St. Joseph High gym after what appeared to be an easy double-digit victory for the Jesters girls’ basketball team heading into the fourth quarter was cast in serious doubt by La Cañada High.

Down by 14 heading into the fourth quarter, it appeared the Spartans were out of hope on the road in the CIF Southern Section Division III-A semifinals Saturday. For one of the first times all night, La Cañada began to click offensively, while simultaneously getting stops on defense.

Just when the third-seeded Spartans had plenty of reason to believe in a comeback, cutting their deficit to six with three-and-a-half minutes left, their major downfalll of the night reared its ugly head — turnovers.

It was the 20 turnovers La Cañada was guilty of Saturday that led to its ultimate demise and ended its hopes of a CIF title in a 50-40 loss to No. 7 St. Joseph.

“Oh my gosh, turnovers, it was just amazing,” La Cañada Coach Tamar Hill said. “It was turnovers with no pressure and missing free throws.

“Our whole halftime mantra was, ‘You need to keep the ball in order to score.’ I wish I knew what was going through a 15-year-old’s head when they throw a ball out of bounds, but they’re just kids. They worked really hard and came really far.”

While the Spartans (20-9) opened the fourth quarter with a 10-2 run to turn a daunting 40-26 deficit at the end of the third quarter to a manageable 42-36 gap, it likely should’ve been closer.

Courtney Chen struggled through the first 24 minutes, but came alive in the fourth quarter and finished with a team-high 16 points after scoring six in the first half.

“They did a good job containing Courtney. They obviously did their homework and they knew they had to put pressure on her and stop her,” Hill said. “We just needed that one other person to step up and unfortunately we didn’t have that tonight.”

St. Joseph’s Michele Pennala scored the first field goal of the final frame on a layup, but Chen sparked a 6-0 Spartans run in about a minute.

The junior point guard drew a foul with 6:47 left in the game and sank both free throws. Chen then added a layup with 5:44 to go to bring La Cañada within 10, 42-32, after a pair of Sarah Borland free throws.

Chen later drove the lane for another bucket to cut into the lead again with 4:29 to play. Marie Weston capped a 12-0 La Cañada spurt when she hit a pull-up jumper with 3:25 to play, prompting a St. Joseph timeout with the home team clinging to a 42-36 lead.

“When it got to six I got really excited,” said Hill, whose team overcame a 14-point deficit in its home quarterfinal win over Santa Margarita, 53-47.

It could have been even closer by that point. Consecutive St. Joseph (19-11) turnovers gave La Cañada the perfect chance to take a lead for the first time with four minutes to play. The Spartans handed the ball right back over each time, as they threw the ball out of bounds and traveled to negate the extra possessions.

The Jesters extended their lead to five, 45-40, when Lauren Hong, who finished with a game-high 20 points and five rebounds, cashed in all her free throws with three minutes to play. La Cañada’s Amber Graves, who had 12 points, added one of her many short jumpers 12 seconds later.

“I think she probably played the best of everybody and she’s the freshman,” Hill said of Graves. “Sometimes ignorance is bliss, you got a kid who doesn’t really know what’s on the line and they just come out and get things done.”

St. Joseph landed a crushing blow by scoring on its next two trips down the floor. Pennala (nine rebounds, five points) sank one free throw after being fouled on a putback attempt with 2:31 to play. St. Joseph’s Jazmine Gandhi (13 points, six rebounds) cashed in an easy layup 21 seconds later after a Ally Painter steal.

Chen hit another jumper, to give her eight points in the fourth quarter, to keep La Cañada within eight with 1:45 to play, but the Spartans wouldn’t score again.

St. Joseph raced out to a 15-4 lead in the first quarter behind a 9-3 rebounding advantage and six takeaways in the opening eight minutes. The Jesters upped their lead to 27-15 at the half.

“Those early shots not falling really hurt us, but we made a great surge and those kids are fighters,” Hill said. “They really wanted it.”

The Spartans had to dig deeper into their bench than desired after Lauren Barsamian and Aundrea Issakhanian picked up two fouls 6:05 and 7:28 into the game, respectively, and sat the rest of the half.

La Cañada saw its deficit grow to 14 by the end of the third, but closed the quarter on a 4-0 run on layups from Chen and Graves in the final 46 seconds.

While the 2013 season ended earlier than hoped for the Spartans, they’re still poised for another playoff run in 2014 with only two seniors graduating and Chen, Borland and Issakhanian returning for their senior seasons, along with a promising class of underclassmen.

“This kind of experience is really valuable, because next year if we’re lucky enough to get in this situation the pressure won’t get to them,” Hill said. “It’ll be old hat to them next year.”