Chonburi's four-match unbeaten run in the Thai League 1 came to a grinding halt on Tuesday night when they suffered a 5-1 hammering at the hands of Bangkok United.
Bangkok United's Sumanya Purisay, left, vies with Chonburi's Ryotaro Nagano.
Buriram United, meanwhile, had little trouble in extending their record as the only unbeaten side in the league this season with a 3-0 victory over bottom-place Super Power Samut Prakran.
Bangkok United had a good start when Chonburi defender Chonlatit Jantakam sent the ball into his own net in the 14th minute.
Bangkok United moved up a gear in the second half and Dragan Boskovic had a hat-trick before Renan Maquez pulled one back for the Sharks.
However, there was more action in the pipeline and Gilberto Macena completed the rout in injury time.
Chonburi coach Therdsak Chaiman said: "Our defence was very bad today. We made lots of mistakes. We need to go back to the drawing board and sort things out."
Bangkok United coach Mano Pokling said: "We are happy with the win especially because this was an away game against a big team. We did well in the second half. We are hoping to be back in the title chase in the near future."
In Tuesday's other matches, Pattaya United could not pick a point after they lost 3-1 to Suphanburi, while Navy drew 0-0 with Police Tero.