Gamba Osaka joined J. League rivals Kashima Antlers in the knockout phase of the Asian Champions League on Tuesday after a 2-1 win at home to South Korea's Suwon Bluewings.
Needing only a point to advance, Gamba fell behind to Jose Mota's header near the hour mark at Expo Stadium, but a superb strike from Takahiro Futagawa made it all square before Takashi Usami snatched the winner deep into injury time.
Gamba top Group G with 11 points, one ahead of Suwon, who had already qualified for the next round. China's Henan Jianye were away to Armed Forces of Singapore in a later match.
"Getting through was our main objective and the players showed a lot of heart tonight," said Gamba manager Akira Nishino. "We have had a crammed schedule and had to chop and change the formation around so with that in mind, I am very satisfied with my players' efforts."
Gamba were missing Hideo Hashimoto and in-form striker Shoki Hirai after both picked up injuries at the weekend to join Yasuhito Endo on the casualty list, and the home side lacked a cutting edge in front of goal in the first half despite some patient approach play.
Usami shot straight at Lee Woon Jae early on before blazing over a half chance on 21 minutes, while Suwon's best opportunity arrived 10 minutes before halftime.