Perennial Thai League 1 title contenders Buriram United and True Bangkok United were both on the receiving end on Sunday night when they suffered unexpected defeats.
While former champions Buriram were beaten 2-1 at home by lowly Nakhon Ratchasima, hosts Bangkok United were edged 5-4 by Sukhothai in a high-scoring affair.
A sparse crowd at Buriram's home ground was stunned into silence in the 27th minute when Swat Cats' Awnnis Murillo found the net with a well-placed low drive.
The Thunder Castle looked better in the second half and a nifty back pass from Jakkaphan Kaewprom allowed Gidi Kanuk to grab the equaliser for the hosts with a long curler on 57 minutes.
However Nakhon Ratchasima were back in command within four minutes as Leandro Assumpcao picked up a cunning short through ball from Amadou Outtara to score from near the top of the box.
Bangkok United lost their fourth match in a row to plummet to seventh place in the table.
Sukhothai's five goals included a brace from Ibson Melo, who scored in the eighth and 45th minutes, and a 38th-minute own goal by Nattawut Suksum. The other two were contributed by John Baggio (62nd minute) and Jung Myoung-Oh (67th minute).
Bangkok United had goals from Thossawat Limwannasathian (39th) and Vander Luis (51st) with Nattawut and Brenner de Oliveira netting in the dying moments of the match.
Also last night, big-spending Port ensured that bottom-placed Rayong remained winless in the top flight with a 7-2 rout in the away game.
Suphanburi claimed a point from their home match against Chonburi, which ended in a goalless draw.
In Saturday night's late game, Alexandre Gama's last match as the head coach of SCG Muang Thong United ended in a 1-0 home loss to Trat.