It’s brutal and unforgiving to this point.

The structure of a 14-team conference (Division I) leaves little room for compromise, so the Oahu Interscholastic Association Red has always been about finishing strong.

Win your regular season without a loss? Big deal. It gets you a bye — along with six of the 10 teams that qualified for the playoffs. But one bad night in the quarterfinals and your season could be done, pau, kaput.

Conversely, a team that goes 3-3 in the regular season, like Waianae, could redeem itself with a glorious night on the road and enter the semifinals with a win.

There, in the semis, even a loss doesn’t mean the end. Since the OIA sends three teams to the six-team D-I state tournament, there is a third-place game to follow. That winner vaults into the state tourney and, only then, is there finality for the last of the hopeful OIA’s postseason squads.

So for hot teams that peak in October and November, it’s a work of art. Go back three years and recall how the Leilehua Mules used a 3-3 regular season to launch into a run-the-table postseason. Quarterback Andrew Manley’s debut, a comeback playoff win at Mililani, was the start of a state championship journey that is still matched by few others.

That’s what makes the OIA playoff system enthralling for its drama yet potentially dangerous for the favorites. Kahuku is No. 1 in the state, but a loss to Radford tonight would end its campaign. It’s happened before: The Red Raiders lost to underdog Kapolei, at Kahuku, in a playoff game just a few years back.

Here’s a look at this weekend’s matchups:

TODAY’S GAMES

OIA Red playoffs

» No. 8 Farrington at No. 3 Mililani, 7 p.m.: The Governors (6-3, 4-3 OIA Red) have struggled against pass-first teams (Castle, Kailua), but this could be even tougher. Mililani coach Rod York invested heavily in pass protection, figuring that quarterback Trent McKinney would be better off airing the ball out than scrambling on every other play — risking injury — against one of the OIA’s hard-hitting defenses.

By moving several of his biggest and best linemen from defense to offense, York, a defensive coach by trade, saw his investment pay off. McKinney has generated 1,927 total yards of offense, running back Zachary Payomo has cracked the 1,000-yard mark (1,020 yards, 10 touchdowns) and the Trojans are scoring 38 points per game.

York said back in July that he’d rather have superior pass pro and win 50-48 than take his chances and see McKinney possibly get injured.

Farrington’s defense will be severely challenged. Linebackers Lance Williams and Justin Vele have been stalwart defenders, but the Govs don’t cover quite as well as they did a year ago.

The Governors will likely grind down Mililani’s defense, which is relatively small and will bend more than it breaks. It’s an interesting development for Farrington’s offensive line, a.k.a. the Bamboolas, and its three sophomores. Can they sustain drives and keep McKinney and Co. off the field?

Mililani (7-1, 5-1) has been knocked back by pulverizing power attacks; its only loss was to Waianae. Farrington’s leading rusher, Scotland Smith (610 yards, five touchdowns), is more of a scatback-type playmaker at 5-7, 145 pounds. Tavale Masalosalo (5-8, 200) and Jordan Hakuole (5-6, 186) have emerged as reliable inside runners. It could come down to quarterback Jared Hakuole’s ability to connect by air when Mililani stacks the box.

» Radford at No. 1 Kahuku, 7 p.m.: The Red Raiders can pack it tight and bulldoze between the hashes. Or they can play-action and find 6-4 tight end Shairone Thompson in single coverage. Or line up in a shotgun set and split Thompson into the slot, or out wide.

Eventually, speedy Punga Vea gets his share of looks on streaks near the sideline. Given a choice, a lot of teams may have given Kahuku quarterback Evan Moe the keys to this mach-speed aerial attack. Instead, coach Reggie Torres opted to stick to his team’s strength in the trenches.

That allowed sophomore Aofaga Wily to rush for 881 yards and 11 touchdowns on just 114 carries. Factor in explosive Tyron Brown (457 yards, nine touchdowns, 6.9 yards per attempt) and fullback Fonoivasa Mataafa up the gut.

Can Radford pull a rabbit out of its bag of tricks? When Kapolei shocked Kahuku in the playoffs a few years ago, hard-running quarterback Mason Koa was a major key. The Rams, though, don’t rely on scrambling passers. Maika Ulufale (1,472 yards, 14 touchdowns) is more conventional, using a variety of targets. Last week, T.J. Reid showed no signs of a midseason MCL sprain and accounted for three touchdowns in their win over Moanalua.

Reid believes Kahuku is beatable in part due to his teammates in the receiving corps: Phil Hogan, Andrew Togiailua, Dorsey Norris and Zach Tinao-Rabellizsa. Kahuku hasn’t seen many teams with this kind of depth in the passing game. But when it has, it won big anyway, beating Saint Louis 49-27 and Castle 52-23.

» Waianae at No. 10 Kailua, 7:30 p.m.: The Seariders have been as erratic as any team, but one pattern has emerged: Scoring is up. After tallying just 16 points in the first three games, Waianae (3-5, 3-3) has scored 29 against Kapolei, 26 in a loss at Leilehua and 41 against Radford.

Defense, though, has been a clear initiator. The Seariders picked off three passes in a 41-20 win over Radford two weeks ago, including touchdown returns of 14 and 45 yards by Kainoa Kauwalu. With an offense that keeps turnovers to a minimum, it’s a winning formula.

That’s what makes this doubly tough for Kailua (5-3, 4-2), which has quick defensive ends in Chevy Mikaele and Ethan Mahaulu and has shown better play in the trenches lately.

Waianae has seen prolific passers and triumphed, as it did in a win at Mililani seven weeks ago. Kailua’s super sophomore, Kahaku Iaea, has passed for 1,953 yards and 15 touchdowns thanks to solid protection and a passing corps that includes Eric Lum (49 catches, 797 yards, nine touchdowns). Lum is also one of the top placekickers in the state.

OIA White playoffs

» Pearl City vs. Kaimuki, Kaiser Stadium, 7 p.m.: The Bulldogs played the Chargers just six nights ago, a 34-12 win for the Bulldogs that mattered little in the playoff scheme. Pearl City (6-3, 5-3 OIA White) used the opportunity to rest key starters, including safety/running back Cyrus Coen.

While the Chargers have a tough defense, the offense remains inconsistent. Coen leads the team in carries (538 yards, nine touchdowns, 8.8 yards per attempt), though he plays full-time on defense. Linebacker Ray Cooper is third on the team in rushing yardage, and the dropoff after that is significant.

Against the White’s top teams, Pearl City scored 30 points in three games. Unless the defense can get more rest, it’ll be a tough challenge again against Kaimuki (8-1, 8-0).

The Bulldogs have permitted just 11.7 points per game. Chester Sua’s otherworldly season has included key plays on defense as a safety and as a kick returner. His 956 rushing yards (12 touchdowns) and coach Clint Onigama’s two-headed quarterback (Dallas Reis, Nahoa Spencer) has worked out well. Mason Kualii-Moe has 21 catches for 352 yards and four touchdowns.

ILH

» Damien vs. Pac-Five, Aloha Stadium, 5 p.m.: The Wolfpack are among the better Division II teams statewide — Pac-Five played Kamehameha to a closer margin of defeat than ‘Iolani did. Pac-Five (2-6, 1-4 ILH) has gotten sparks of offense from running back Darius Anderson and wide receiver Everett Kim. Damien (0-8, 0-6) has kept battling.

» No. 9 Kamehameha vs. No. 6 Punahou, Aloha Stadium, 7:45 p.m.: It was not long ago when these teams were duking it out for supremacy in the ILH. Now, this matchup is for pride and standings. Defending state champion Kamehameha (5-3, 3-2) has missed last year’s outstanding senior class. Punahou is 5-3, 3-3 ILH.

TOMORROW’S GAMES

OIA Red playoffs

» Castle at No. 4 Leilehua, 7 p.m.: The Knights’ passing potency was a given with returnee Jaymason Lee (1,861 yards, 13 touchdowns), but Leilehua? The Mules (5-2, 5-1 OIA Red) had to rely on defense and special teams this season.

"We find ways to win," coach Nolan Tokuda said.

Oh, they’ve found an old way to win, no question. The offense has exploded. Kenan Sadanaga and Jordan Kalaau have combined for 1,542 passing yards and 16 touchdowns, and receiver Darrien Shealy has been almost perfect. The 6-1 175-pound senior rarely drops a pass and has 35 receptions for 541 yards and five touchdowns.

Fred Padrones has been equally effective (30 catches, 480 yards, six touchdowns), while Jeremiah Andrade, Allen Racette and Elijah Barro have turned in timely plays.

The lack of a consistent running game is a trait shared by both teams. Castle (5-3, 3-3) has gone to Joshua Kong (30 catches, 550 yards, five touchdowns).

OIA White playoffs

» Kalaheo at Waipahu, 7 p.m.: When they met four weeks ago, the Mustangs (5-3, 5-3 OIA White) had a 14-0 lead, a 20-10 lead at halftime, and looked more like a passing juggernaut than a veer-option team. By the end, however, they had no way to counter the onslaught of Waipahu (6-2, 5-2) and Victor Moananu, who finished with 36 carries for 214 yards and two touchdowns.

More surprising, though, was the way Waipahu’s defense shut out the Mustangs in the second half for a 31-20 win, and how Jesse Carney was limited to 24 yards on the ground.

KIF

» Kapaa at Waimea, Hanapepe Stadium, 3:30 p.m.: Last week’s 14-13 loss to Kauai put the Warriors in a tough spot. One more loss and Kapaa (5-2, 3-2 KIF) would be mathematically eliminated from title contention. It won’t come easy; Kapaa left Waimea with a 7-0 win six weeks ago.

MIL

» No. 5 Baldwin vs. Maui, War Memorial Stadium, 7 p.m.: The days of a great football rivalry between these two programs seems to have passed. Baldwin (6-1, 5-0 MIL) shut out Maui 52-0 four weeks ago and has allowed just 43 points in league play. The Sabers (1-5, 0-5) have the difficulty of playing in a traditionally strong football league. They haven’t tasted a win since a nonconference game with Waiakea, a 33-0 rout.

» King Kekaulike at Lahainaluna, 1:30 p.m.: Oahu coaches and media haven’t given the Lunas (5-1, 4-1 MIL) much credence in the poll, possibly because they haven’t played a ranked team besides Baldwin. For now, the Lunas have their sights on another D-II title. Na Alii (3-5, 2-5) lost to Lahainaluna 35-12 on Aug. 28.

BIIF

» Kamehameha-Hawaii at Hawaii Prep, 2 p.m.: Losing not one, but two quarterbacks put Ka Makani (6-2, 5-2 BIIF) and their title hopes in a quandary. The visiting Warriors (9-1, 9-0) just need one more win in their final two games to clinch the Big Island’s top D-II seed.

» Kohala at Ka’u, 5 p.m.: The Trojans’ turnaround season could get another highlight with another win over the Cowboys. Ka’u (2-6, 2-6 BIIF) won at Kohala (0-6, 0-6) 32-22 on Sept. 18. The Trojans haven’t won since.