The Purdy girls missed a game-winning shot as time expired to fall 35-34 to the Lady Indians.
The Purdy boys were sunk when Kyler Ng drilled a 3-pointer with 5.1 seconds remaining to give4 Seneca the 49-46 victory.
Purdy's girls got off to a slow start and fell behind 10-5 after one quarter of play.
Katie Hughes provided a spark off the bench for the Lady Eagles in the second period, scoring 5 quick points to pull the black and yellow to within 14-10.
Purdy looked like a totally different team in the second half.
A crisp, aggressive and opportunistic Lady Eagles squad opened the third quarter with a 12-0 push to take a 25-23 lead.
Purdy held a 27-26 edge after three periods.
Mattie White's deuce and a Courtney White free throw to open the final quarter lifted Purdy to a 30-26 advantage.
The Lady Indians fought back with a basket by Mirana Heath and a trey by Courtney Cook to take a 31-30 lead with 4:07 left.
At the 3:09 mark, the Lady Indians' Molli Cooper broke a 32-32 tie with a 3-pointer from the right elbow.
Mattie White responded with a layup with a minute left. The Lady Eagles took three shots in the final minute to try to take the lead but couldn't get the ball through the hoop.
"We played one bad half and one really good half tonight," said Purdy coach Eli Ernst. "We have got to figure out how to play for all four quarters. I liked our energy in the second half. We just didn't finish."
Scoring for Seneca: Cooper and Heath, 12 points each; Bailey Skelton and Cook, 4 apiece; and Annie Howard, 3.
Scoring for Purdy: Mattie White and Ennis, 8 each; Hughes, 7; Jayse Henderson, 5; and Billie House and Courtney White, 3 apiece.
The Purdy Eagles squandered a 9-point first-half lead, then erased an 8-point deficit in the fourth quarter before falling 49-46 to Seneca.
"It boils down to fundamentals," said Purdy coach Tommy Egan. "We struggled to keep Seneca off the offensive boards, and tonight, it cost us."
The Eagles controlled the first period using their speed in transition to beat the Indians down the court to take a 16-10 lead.
Seneca slowed the pace in the second quarter and outperformed the Eagles 15-10 to trail 26-25 at halftime.
Seneca, behind Ng's leadership, surged to a 39-33 lead after three periods.
The Indians pounded the ball into the paint and used their size to outmuscle the Eagles on the glass during the third quarter surge.
Purdy wouldn't fade and came out firing in the fourth quarter.
Alex Mareth started a 7-0 run with a 3-pointer then a five-foot jump shot. Austin Hancock completed the run with a layup.
Purdy tied the game at 44-44 on Tyler Scott's 3-pointer with 2:59 remaining. Hancock gave the Eagles a two-point lead with 1:54 left but Chance Smith's offensive board and put-back tied the game with 1:05 remaining.
After an Eagles' turnover with 15 seconds left, Ng worked free at the top of the key, catching a pass and shooting in rhythm to lift Seneca to the 49-46 victory.
Scoring for Seneca: Ng, 17 points; Logan St. Clair, 10; Smith, 8; Elias Roelfsema, 7; Bradley Jumper, 5; and Seth Harris, 2.
Scoring for Purdy: Mareth, 13 points; Glenn Scott, 12; Tyler Scott, 10; Hancock, 7; and Keevin Walker, 4.