Mercer Island, Interlake and Redmond will decide who gets the final two postseason berths out of KingCo 3A with a three-team playoff Tuesday night at Juanita High School.

After Mercer Island’s 24-14 upset win over the Juanita Rebels in its KingCo league finale Friday, the Islanders (4-5, 2-3 in KingCo) found themselves tied with Redmond (3-6, 2-3) and Interlake (6-3, 2-3) in conference standings for the league’s final two playoff spots.

And so, the three teams will square off in two “mini-games” for the league’s second and third playoff seeds, Mercer Island head coach Brett Ogata told the Reporter. Interlake and Redmond will compete in a two-quarter contest, with the winner earning KingCo 3A’s second seed.

After a 20-minute “halftime” period, the loser will take on Mercer Island for the third seed in a second two-quarter game. The matchups were decided by coin flip Friday night, Ogata said.

The Islanders were already clinging to their playoff lives heading into Friday’s game against the Rebels (4-4, 3-2), who secured KingCo’s top seed with Bellevue (5-1, 5-0) ineligible for postseason play due to sanctions handed down from the league.

But behind a defense that limited the Rebels to six points through the first three quarters of play, the Islanders stormed out to a 24-6 advantage and held off the Juanita offense down the stretch.

Interlake and Redmond are scheduled to kick off at 7 p.m. Tuesday night in Kirkland.