BG Pathum United took an unassailable three-point lead at the top of the AFC Champion League Group G table following a goalless draw with Jeonnam Dragons last night.
The result at the Rabbits' home ground was enough to assure them of a place in the last 16 stage of Asia's premier club competition for the first time in the club's history.
Pathum, the former Thai League 1 champions, surged three points ahead of second-placed Melbourne City at the end of their last Group G game.
Melbourne City were to play United City of the Philippines in the final group fixture last night.
Pathum United dominated their South Korean opponents from the start and had it not been for a couple of misses by veteran Thailand striker Teerasil Dangda they would have been assured of No.1 spot in the pool.
Their first chance came as early as the second minute of the match when Teerasil sent a Jakkapan Praisuwan cross flying way over the bar from the middle of the box.
Chatmongkol Tongkiri gave Teerasil another opportunity to make amends but his left-footed shot missed the right post in the 16th minute.
Jeonnam Dragons came close to stealing full points from the match but Leonard Pllana was equally erratic six minutes after the break.
Pathum United kept pressuring their opponents but found it difficult to make any meaningful inroads.
Pathum United's star striker Diogo Luis Santo saw his shot saved by Jeonnam goalkeeper five minutes from time as the two teams ended up sharing the spoils.
Pathum United ended their quota of six matches with three wins and an equal number of draws, firing 11 goals and conceding only two in the process.
Chiang Rai United were the other Thai team to reach the group stages of the tournament.
The Beetles were eliminated from the competition after securing only one point from four matches at the end of their Group J games on Thursday night.
Japan's Vissel Kobe look set to finish as the group winners after three straight victories with Kitchee United of Hong Kong settling for the second place.
There are only three teams in Group J.
Meanwhile, Samut Prakan continued their campaign to avoid the drop with a 2-1 home victory over Khon Kaen United in Thai League 1 last night.
Chiangmai United, who have already been relegated to the second tier, pulled off a 1-0 upset over Police Tero at their home ground.