KAILUA - With its postseason hopes in danger, Castle stunned Kailua, 26-17, Saturday night in O'ahu Interscholastic Association Red East football.

The Knights (6-2 overall, 3-2 Red East) secured a berth to the 10-team OIA tournament in spoiling the Surfriders' homecoming before an overflow crowd of about 2,000 at Kailua's stadium. Kailua (5-3, 4-2), ranked seventh in the ScoringLive-OC16 Power Rankings, ended its regular season, but has clinched a postseason berth. It will finish either second or third, depending on Castle's outcome against Kahuku next week. The top five teams from each division qualify for the OIA tournament.

"This was really a must-win game for us," Castle coach Nelson Maeda said. "The way the East has been, if we had lost this game and looking at Kahuku next week and Roosevelt doing as well as they did, we could've been the odd team out. We knew the predicament we were in and knew what we had to do."

QB Jaymason Lee passed for 197 yards and two touchdowns for the Knights.

"We knew these guys were tough," Lee said of Kailua. "They have good D-linemen; we knew they could put on the pressure, but we prepared really hard for this. Our line gave me a lot of time."

Kailua, which had a five-game win streak snapped, felt the effects of the loss of 5-foot-11, 210-pound RB Isaac "Bubba" Sato, who suffered a season-ending knee injury against Farrington two weeks ago.

The Surfriders pulled to 20-17 midway through the third quarter on Kahaku Iaea's 19-yard TD pass to Kila Zuttermeister and Jarrin Young's 2-point conversion run.

Ethan Mahaulu intercepted Lee on the Knights' ensuing series, returning the ball 28 yards to the Castle 6. But Kailua struggled to move the ball in an area that Sato would've been valuable. Instead, the Surfriders went for a 22-yard field that went wide right.

The Knights sealed the game on their next series, moving 80 yards in seven plays with Lee hitting Moses Alimoot on a 17-yard TD pass early in the fourth quarter that made it 26-17.

"Jarrin did a great job filling in," said Kailua coach Gary Rosolowich, referring to RB Jarrin Young. "But (Sato's injury) thins our ranks, especially in short-yardage situations. Obviously, having Bubba would be a plus, but that's not why we lost."

Castle's defense didn't sack Iaea, but it did get five interceptions, two by linebacker Cy Pana. Noah Makainai, Joshua Kong and Layne Suyat each had one pick. Iaea was contained to a season-low 144 yards passing.

"We've had our struggles with our defense, but they did the job tonight," Maeda.

Kailua took a 3-0 lead on Eric Lum's 40-yard field goal, but the Knights followed with three TDs on runs of one yard by Olycon Finau and three yards by Jaques Hough and a 22-yard TD pass from Lee to Makainai.

Kailua pulled to 20-17 on a 66-yard TD run by Young and Zuttermeister's TD catch. But the Surfriders could not capitalize on Mahaulu's interception.