Jubilo Iwata will face a playoff to remain in the first-division after a 94th-minute own goal by captain Kentaro Oi gave Kawasaki Frontale a 2-1 victory and sent the visitors plummeting to the bottom three in the J-League final round on Saturday.
At the other end of the table, Asian Champions League winners Kashima Antlers will have a chance to defend their continental title next year after holding onto third place with a scoreless draw against visiting Sagan Tosu.
Starting the day 13th, Jubilo held a one-point buffer over a trio of clubs -- Shonan Bellmare, Sagan and Nagoya Grampus -- who were also looking to avoid a 16th-place finish and subsequent relegation playoff against a second-division side.
But with Sagan holding Antlers to a stalemate, and Shonan drawing 2-2 away to Grampus, all three leapfrogged Jubilo on goal difference.
Veteran forward Yoshito Okubo gave Jubilo the lead with a well-taken 78th-minute header at Todoroki Stadium, but Tatsuki Nara headed an equalizer from a corner just five minutes later.
Frontale, who clinched their second straight J-League title with two rounds to spare, continued pressing for a late winner. When Akihiro Ienaga sent a cross to Kei Chinen in the dying moments of injury time, the 23-year-old striker looked to have scored with a lunging effort.
But replays showed center back Oi deflecting the ball into his own net in a desperate effort to stop it reaching Chinen.
Jubilo will meet the winner of Sunday's playoff between J2 sides Yokohama FC and Tokyo Verdy in a one-match decider.
Bellmare and Grampus came into their clash at Paloma Mizuho Stadium knowing a win would guarantee the victor a place in the first division next year.
First-half goals to Shunsuke Kikuchi and Tsukasa Umesaki saw Bellmare take a 2-0 lead into the break, but league top-scorer Jo struck from the penalty spot in the 67th minute, and again eight minutes later, to salvage the draw.
Kikuchi gave Bellmare the lead in the 19th minute when he tapped in a Daiki Kaneko cross from close range. Grampus keeper Mitchell Langerak got a hand to the ball diving to his right but was unable to keep it out.
Bellmare doubled the lead with nine minutes left in the half when Umesaki converted from the penalty spot after Langerak clumsily tripped right-back Miki Yamane in front of goal.
Jo won his Grampus' first penalty after theatrically going to ground in a goal-box tussle with a pair of defenders as his team looked to play an aerial ball to the Brazilian striker.
The second came on a handball by defender Keisuke Saka. With Jo at the penalty spot, Bellmare keeper Yota Akimoto correctly anticipated the direction of the kick each time but was unable to get a stop.
Consadole Sapporo came into the final day looking to book their maiden ACL berth by moving past Antlers with a win over second-place Sanfrecce Hiroshima.
The Hokkaido club seemed on track to realize the goal after taking a 2-0 lead early in their clash at Sapporo Dome.
Chanathip Songkrasin scored just three minutes in, firing home first-time after Jay Bothroyd laid off a ball to the Thai international at the edge of the area. Bothroyd doubled the lead 18 minutes later with a spectacular chipped goal from 35 meters out.
But goals either side of halftime to Kazuaki Mawatari and Kosei Shibasaki forced Consadole to settle for a draw and a fourth-place finish.
In a battle for fifth and sixth place, Tadanari Lee scored a brace as Urawa Reds beat FC Tokyo 3-2 at Saitama Stadium and finished above the visitors.
At Nissan Stadium, Yokohama F Marinos capped off their first season under former Australia manager Ange Postecoglou with a 2-1 loss to Cerezo Osaka. The result saw Marinos finish 12th, while Cerezo climbed to seventh.
Vissel Kobe secured a 10th-place finish by beating Vegalta Sendai 3-2, but the biggest news out of Noevir Stadium was the home side's recruitment of former Spain international David Villa, who announced the move via social media while attending the match.
Already-relegated Kashiwa Reysol beat visiting Gamba Osaka 4-2, consigning them to a ninth-place finish, while last-place V-Varen Nagasaki said farewell to the first-division with a 4-4 draw against visiting Shimizu S-Pulse.