Bangkok United are assured of a berth in the last 16 of the AFC Champions League Two despite a 1-0 defeat at Tampines Rovers on Wednesday night.
The Thai League 1 leaders were beaten by a Seia Kunori winner in the 61st minute but guaranteed themselves a place in the knockout stage due to a superior head-to-head record, having beaten the Singaporean outfit 4-2 in the reverse fixture.
The Angels are second in Group G with 10 points while Tampines, who have been eliminated, are third with seven points with one game remaining.
They will face Vietnam's Nam Dinh FC next week to decide the group winners, with the Vietnamese side also having confirmed qualification after a 3-0 win over Hong Kong's Lee Man.
"We created many chances but lacked accuracy. Had we scored, the outcome of the match would have been different," said Angels coach Totchtawan Sripan.
The Angels will now turn their focus to the domestic league where they will visit BG Pathum United on Sunday.
Prachuap face Swat Cats
Hosts PT Prachuap will take on Nakhon Ratchasima at their Sam Aoh Stadium in the Thai League 1 on Friday.
Fourth-placed Prachuap drew 0-0 with Lamphun Warriors in their previous game while the Swat Cats edged BG Pathum United 1-0 to move up to eighth spot in the standings.