This was not an uneventful football game in which lower-tier teams were playing out the string.

Neither combatant — Kailua and Castle — was going for a title in Saturday night’s regular-season ender, but that potent rivalry elixir was on tap for the winner as well as a higher seeding for the first round of the Oahu Interscholastic Association playoffs next weekend.

Windward pride and bragging rights on this night went to the visiting Knights, who held off a sturdy Surfriders comeback for a 24-21 victory.

Now both teams head into the playoffs with a hard-hitting, rough preparation game behind them. With the win, Castle (4-4, 3-4) earned the OIA Red’s No. 5 seed and will travel to play Moanalua, the Blue’s No. 4 seed, next weekend.

Kailua (3-4, 3-4) dropped to the Red No. 6 seed and will travel to play Blue No. 3 seed Waianae in the first round for the second year in a row.

“It sure was exciting,” Knights coach Nelson Maeda said. “There’s nothing like a Kailua-Castle game over here.”

Indeed. Castle grabbed a 21-0 lead and was in complete command until the Surfriders sensed the game being taken away and did something about it.

Fortunately for the Knights, Cheyden Costa kicked a 34-yard field goal with 1:58 left in the game for an important 10-point, 24-14, cushion.

Kailua was far, far from done. Chauncy Gonsalves-Bell returned the kickoff 45 yards and, five plays later, quarterback Mark Lagazo was in the end zone with a 5-yard touchdown to make it 24-21 with 33 seconds to go.

Tanner Wright recovered Kailua’s onside kick and the Surfriders drove to the Castle 18. Lagazo threw a ball intended for Hapaki Kupahu-Phillips, but the Knights’ Blaize Rickard picked it off to seal the victory with 10 ticks left. It was Rickard’s second interception of the game.

“We started flat in the first half, but we fought hard to the end,” said Lagazo, who rushed for 112 yards. “It was unlucky that we didn’t come out with the ‘W.’ ”

Israel Pakele was the force behind the Castle offense. He ran for 149 yards on 18 carries and scored his team’s first two touchdowns with runs of 30 and 14 yards, and those scores were set up by Kawelo Kalauokalani’s fumble recovery and Rickard’s first interception.

“If there was a game ball to be given, it would definitely go to (Pakele),” Maeda said. “He ran hard tonight. He provided a running game and some consistency to the offense and he doubled as a linebacker. He’s also a kicker and a multi-purpose player for us.”

An interception by Castle’s Chasen Palaylay-Shuford led to the Knights’ third touchdown. This time, wildcat quarterback Jeremy McGoldrick scored on a 10-yard run for a 21-0 lead with 3:58 to go in the third quarter.

Kailua coach Joe Wong lamented the turnovers — five in all.

“Sometimes that’s how the game goes,” he said. “The breaks of the game. Sometimes you have too many turnovers that you cannot come back from. But they did. They fought to the very end. They showed their resiliency. I wish that we didn’t wait that long (to get back into the game). We moved the ball down the field, but it was just the turnovers, man. Castle made the plays when they needed to.”

Lagazo powered the Kailua comeback. His 4-yard run capped a 90-yard drive for a 21-7 count early in the fourth quarter. After the Surfriders’ Dakota Kadooka recovered a Knights fumble, Lagazo found Christian Mejia with a 15-yard TD strike to make it 21-14 with 9:02 remaining.