Defending champions and leaders Buriram United dropped points only for the second time in Thai League 1 this season on Saturday night when they were held to a 1-1 draw by visiting Lamphun Warriors.
Buriram coach Osmar Loss called it "a disappointing day" after the match.
"For the second week in a row our players didn't get enough space to play their game, so we need start looking for a solution now. We should have been quicker in the offence. The players kept trying but it wasn't enough," said the Brazilian coach.
Lamphun were the first to score with Ricardo Lopes finding the net in the 46th minute.
The Thunder Castle equalised from a penalty awarded after Supachai Chaided was fouled by a Lamphun player inside the box. It was Guilherme Bissoli who stepped up and made no mistake from the spot.
Lamphun were left with 10 men in the 75th minute when Nuttee Noiwilai fouled Phitiwat Sukjitthammakul and the match referee flashed the red card after consulting the VAR.
Elsewhere on Saturday night, BG Pathum United picked up three points after a convincing 3-1 victory over Nakhon Pathom United.
Shinnaphat Leeaoh put Pathum ahead in the 27th minute but Nakhon Pathom equalised in the first-half injury time. The Rabbits had two more goals in the second half through Airfan Doloh (66) and Brazilian Freddy Alvarez (90).
Sukhothai pulled off an incredible 3-1 victory over Rayong in a home game despite being left with nine men for almost 30 minutes.
Meanwhile hosts Khon Kaen United shared a point with Nakhon Ratchasima after a goalless draw.