Yuya Osako earned Kashima a 2-1 win at Shonan Bellmare in the most dramatic of circumstances, as the forward netted just a minute after Wataru Endo's 91st-minute equaliser for the hosts.
Mitsuo Ogasawara opened the scoring for Toninho Cerezo's men in the first half, but it looked like Endo had done enough to earn a point for Shonan.
However, Osako had other ideas, as he made it six wins from Kashima's last seven league outings in the dying seconds.
The result all but condemns Shonan to relegation with three games remaining, as Kashima took full advantage of Yokohama F Marinos, Urawa Reds and Sanfrecce Hiroshima all failing to win.
Leaders Yokohama fell to their first home defeat of the season as mid-table Nagoya Grampus earned a shock 2-1 win at the Nissan Stadium courtesy of an early Josh Kennedy penalty and Jungo Fujimoto's second-half strike, which sandwiched a Shingo Hyodo leveller.
Second-placed Urawa were denied three points at Vegalta Sendai thanks to Jiro Kamata's 92nd-minute leveller, which earned the hosts a 3-3 draw after they had twice been behind.
Meanwhile, Sanfrecce, who currently occupy the third and final Champions League place, needed a 79th-minute equaliser from Toshihiro Aoyama to draw 1-1 at Kashiwa Reysol.
These scores mean that, with just three points now separating first and fourth with three matches left, the battle for the title and Champions League football looks set to go to the wire.
Cerezo Osaka also kept themselves in touch with the top four with a hard-fought 2-1 victory at Tokyo.
Tokyo's Aria Hasegawa equalised Takumi Minamino’s first-half opener for the visitors with 20 minutes remaining, but Yoichiro Kakitani struck in the 88th minute to give Cerezo the win.
Elsewhere, Kawasaki Frontale made it three top-flight home wins in a row with a comfortable 2-0 success over Shimizu S-Pulse, Yoshito Okubo grabbing a second-half double for the hosts.
Albirex Niigata comprehensively overcame the already-relegated Oita Trinita 3-1 at the Oita Bank Dome, while Ventforet Kofu claimed an impressive 2-1 victory at Omiya Ardija.
In Sunday's other fixture, second-bottom Jubilo Iwata lost their fifth straight J.League game with a 1-0 reverse at Sagan Tosu.
