Poteet entered Tuesday still alive in the playoff race, but knew it had to defeat Forney to keep those hopes going.
The Pirates battled down to the wire, but the Jackrabbits were able to do just enough down the stretch to claim a 59-54 victory.
Poteet falls to 4-9 on the 13-5A season and is eliminated from the postseason race.
The teams were tied after one quarter, but Forney was able to edge out to a 30-21 halftime advantage.
The Pirates did not go down without a fight, and clawed back to within 41-39 at the end of three quarters, but the Jackrabbits were able to fend off the comeback attempt.
That win allowed Forney (6-7) to move ahead of Greenville (5-8) by one game in the battle for the final spot.
Both teams face tough challenges in the finale, as Forney hosts Crandall (9-4) and Greenville goes on the road to take on North Forney (10-3).
Crandall actually crept to within a game of the Falcons on Tuesday with a 54-49 head-to-head win, getting 28 points from freshman Marlon Linton, Jr., and 17 from Beau Bragg.
Highland Park (13-0) continued its roll to an undefeated district championship with a 69-37 win over Greenville.
Worthey Wiles scored 17 points, Jack Pease had 11 and Camp Wagner added nine as the Scots opened a 33-14 halftime lead and never looked back.
Poteet and West Mesquite (1-11) will each try to end the season on a high note on Friday when the Wranglers host the Pirates.