Suphanat Mueanta struck three minutes into stoppage-time for the hosts after Jang Si-young had cancelled out Guilherme Bissoli’s 20th-minute opener for the Thai side in first half stoppage-time.

Ulsan have three points from seven games and are five adrift of the top-eight places that secure berths in the next phase of the competition with one round remaining.

Buriram climbed to sixth on 11 points and a draw against already-qualified Gwangju FC on Tuesday would be enough to take them into the next phase.

The first eight finishers in east and west Asia advance to the round of 16, which will be held on a home-and-away basis in March.

The quarterfinals, semifinals and final will be played in a centralised format in Saudi Arabia in April and May.

Bissoli capitalised on a slip in midfield by Jung Woo-yong to crash his shot beyond Jo Hyeon-woo but Jang levelled with a deft finish following Darijan Bojanic’s measured through ball.

The game looked destined for a draw until Suphanat pounced, the Thai striker sliding in at the far post to crash Dion Cools’ cross from the right into the roof of the net.

Yokohama F Marinos climbed back into top spot with a 1-0 win over Chinese Super League side Shanghai Shenhua in manager Steve Holland’s first game in charge of the Japanese club.

Yan Matheus scored the only goal in the 20th minute when he bent his shot into the top corner after Anderson Lopes’ clever back heel wrong-footed the Chinese side’s defence.

Marinos, who had secured qualification after yesterday’s results meant they could not finish outside the top eight, lead the standings on goal difference from fellow J-League side Vissel Kobe.

Kobe, third-placed Kawasaki Frontale and Gwangju FC have all qualified for the next phase.