It was the lowest point total of the season for the Eagles (5-16). Their previous low had been 35 twice.
South Putnam made 9-of-56 field goal attempts including 1-of-7 3-pointers and were 3-of-6 at the foul line.
The Eagles led 6-5 and Jessica Thompson's 3-pointer kept them close, trailing 12-9, at the end of the first quarter.
South Putnam went scoreless in the second quarter, missing 11 straight field goal attempts, and Speedway (12-7) pulled away to a 24-9 advantage.
"I thought we came out and played with real good intensity in the first quarter," South Putnam coach Debbie Steffy said. "We stuck to our game plan, we did what we wanted to do. The second quarter, we tried to do the same thing and we came up scoreless and that just put us under a pile we could get out from under for the rest of the game."
Emily Dabkowski scored the opening four points of the third quarter and Brooke Boetjer's basket inside following an offensive rebound sparked a brief South Putnam rally, cutting the Sparkplugs' lead to 25-15.
But Speedway countered with a 9-0 run and even though the Eagles scored 12 points in the third period, it ended with them trailing 37-21.
The Eagles went 0-of-9 from the field and 1-of-4 at the foul line in the fourth quarter.
"The second half, we had to go man-to-man and they took advantage of that and tried to beat us off the dribble," Steffy said. "I can't fault our kids' effort. They worked hard. They played hard."
Speedway had defeated South Putnam 53-40 on Dec. 18 in their West Central Conference game.
"It was a team we had gotten beaten by earlier in the season and so it was one of those it could go either way," Steffy said. "It was like, 'Are they going to be motivated for that?' Or, is it going to be one of those where they look at it and say, 'OK, there's no way we can beat this team.' I've got to give my kids credit. They came out and they played hard They worked hard in practice. Everybody was in the same situation this week. It was a weird week as far as practices. You get hyped up to play a game and all of the sudden, you don't play. I want to give our kids credit, they handled that situation very , very well as far as the adversity with the weather."
Steffy thought Speedway's defensive game plan contributed to South Putnam's shooting problems..
"You've got to give Speedway credit, too," Steffy said. "They played a 3-2 zone because they knew we were going to try to penetrate to the basket and try to give it to our post players and they tried to take both away."
Dabkowski led South Putnam with 12 points and had seven rebounds. Boetjer had a game-high 11 rebounds.
It was the final game at South Putnam for the Eagles' sole senior, Jessica Thompson. She had five points and two rebounds.
"Jessica played very hard," Steffy said.
Speedway will play Tri-West tonight at 7:30 p.m. in the sectional semifinal. Monrovia plays Covenant Christian in the first semifinal at 6 p.m.
At North Putnam
Speedway 12 12 13 11 -- 48
South Putnam 9 0 12 1 -- 22
Daghe 3-8 2-2 10, Walton 1-1 0-0 3, Anglea 2-9 3-4 7, Coates 5-5 5-8 16, Jones 3-6 1-2 7, Gregory 0-0 0-0 0, B. Smith 1-2 2-4 4, R. Smith 0-0 1-2 1, Tavis 0-0 0-0 0, Totals 15-31 14-22 48.
SOUTH PUTNAM 22
Dabkowski 5-17 2-3 12, Jes. Thompson 2-15 0-0 5, Minor 1-5 0-0 2, Boetjer 1-6 1-2 3, Jones 0-1 0-0 0, Jen. Thompson 0-1 0-0 0, Searles 0-3 0-0 0, Masters 0-2 0-0 0, Varvel 0-4 0-0 0, Goodpaster 0-3 0-0 0, Totals 9-56 3-6 22.
3-point field goals -- Speed 4-8 (Daghe 2-5, Walton 1-1, Coates 1-1, Jones 0-1), SoPut 1-7 (Jes. Thompson 1-3, Dabkowski 0-2, Jones 0-1, Goodpaster 0-1). Rebounds-- Speed 32 (Coates 8), SoPut 36 (Boetjer 11, Dabkowski 7, Searles 6). Turnovers -- Speed 14, SoPut 14. Total fouls -- Speed 9, SoPut 16. Fouled out -- None.