Super-sub Ito fires champs Kashima into Asian knockouts
Former Manchester United midfielder Marouane Fellaini headed the Group E winners in front after 10 minutes, the beanpole Belgian powering the ball after good work from Brazilian Gil to give the hosts a scare.
But the Antlers, who only needed a draw to join Shandong in the last 16, struck back in the 68th minute when Ito smashed home from close range after the visitors failed to clear a Leo Silva corner.
Moments later, Ito beat the offside trap and applied a clinical finish with the outside of his right boot to turn the game on its head.
The Antlers, who kept Asia's premier club title in Japan after J-League rivals Urawa Reds won it in 2017, had lost their previous two games.
But a much-needed victory in their final group match boosted their points tally to 10 points from six games, one behind their opponents.
Kashima's comeback meant Korean side Gyeongnam's 2-0 victory over Johor Darul Ta'zim was academic.
Luc Castaignos fired the K-League club ahead a little after the hour mark to break stubborn resistance from the Group E minnows before Takahiro Kunimoto added an injury-time second for the home side.
Kashima will play Japanese rivals Sanfrecce Hiroshima in the knockout stages with Shandong facing China's two-time Asian champion Guangzhou Evergrande.