The Bulldogs used clutch shooting and solid defense to hold off the Eagles 65-61.
In the nightcap, the Lady Eagles cruised to a 68-18 victory.
Wheaton built a 17-12 advantage after one quarter of play and led by as many as 11 (32-21) in the second period.
Brent Cornman, with four quick points, helped key an 11-4 push by Purdy to close the gap 36-32 at halftime.
"We are still a young team that has a ways to go before we mature on the court," said Purdy Tommy Egan. "In the first half, it seemed like Wheaton beat us to every loose ball. We battled back but didn't make enough plays."
The first two minutes after halftime foreshadowed the entire second half.
The Eagles pulled close (36-34) with Glenn Scott's bucket to open the third period, only to watch a 3-pointer by Matt Hickman and a short jumper by Darrell Burns re-establish a Bulldogs' cushion.
On 12 more occasions in the second half, the Eagles trimmed the margin to 3 or less including a tie at 53-53 with 3:20 left in the game.
Wheaton seniors Jory Bartkoski and Justin Yeary took turns hitting shots to answer all 12 times.
"Jory is starting to play at the level we expected him to," said Roe. "All of our seniors stepped up in the crunch to carry us tonight."
Scoring for Purdy: Cornman, 21 points; Glenn Scott, 12; Alex Mareth, 9; Keevin Walker, 7; Tyler Scott and Austin Hancock, 4; and Cameron Terry, 2.
Scoring for Wheaton: Bartkoski, 21 points; Yeary, 20; Hickman, 7; Burns, 6; Chase cantwell, 5; and Steven Hendrix, Tyler Musick and Justin Walker, 2 points each.
Purdy and Wheaton girls
In the second tilt of the evening, Purdy handled Wheaton 68-18.
The Lady Eagles scored the game's first 20 points and led 24-3 at the end of the first period.
The young Lady Bulldogs squad struggled with the Purdy pressure and trailed 39-9 at halftime.
Scoring for Wheaton: Kelly Alvarado, 6 points; Amanda Munday, 5; Shelby Medley, 4; Jera Prewitt, 2; and Crystal Alvarado, 1.
Scoring for Purdy: Desirie Ennes, 21 points; Mattie White, 15; Abby Parsons 8, Courtney White, 7; Kat Hughes, 6; Andrea Humphrey, 5; Katie Hughes, 4; and Ashton Young, 2.