Muang Thong United secured their place in the knockout stage after a dramatic 1-0 victory over Jeonbuk Hyundai Motors in the AFC Champions League Two at Rajamangala Stadium on Thursday night.
Purachet Thodsanid scored a minute into first-half added time to earn Uthai Bunmoh's side the win needed to take the runners-up spot in the Group H standings and join Jeonbuk in next week's draw for the knockout rounds.
The Kirins have 11 points from six games, one clear of Malaysia's Selangor, who recorded a comprehensive 4-0 win over Dynamic Herb Cebu in Manila.
Kirins coach Uthai Boonmoh was visibly thrilled after the match.
"Thank you to everyone, from the players to the staff and everyone involved," he said. "The players gave their all, and I'm very happy with the win. The most important thing is to go to the next round. The moment we scored, I knew we had qualified. That was what was going through my mind."
Meanwhile, Port were beaten by Lion City Sailors FC 5-2 to finish second in Group F.
The Singaporean side finished level on 10 points with Port but topped the group on superior goal difference, having also beaten the Thai League 1 side 3-1 in the reverse fixture.
Song Ui-Young starred with a hat-trick for the Sailors.