By ESPNSTAR.com staff
Just days after their heartbreaking Thai League Cup quarter-final exit at the hands of Buriram United, BEC Tero were beaten 2-0 by relegation-threatened Thai Port at the Thephasadin Stadium.
Korea DPR international Ri Myong-jun opened the scoring for Port in the 15th minute, before Alex da Costa made sure of the three points when he added a second in injury-time.
Glass, who have spent much of this season in the top five, slipped to sixth after falling to a 3-2 loss at Samut Songkhram.
Thai international Teeratep Winothai gave the Glass Rabbits a dream start when he fired them in front in the 17th minute, but Bireme Diouf equalised for the hosts eight minutes later.
Songkhram then went ahead in the 32nd minute thanks to a Park Jae-hyun strike, only for Brazilian defender Rafael to pull the visitors level three minutes later.
However, it was not to be for Glass as Diouf grabbed his second of the game 16 minutes from time to hand his side all three points.
The result also meant Esan United moved up to fifth after they beat Police United 1-0, courtesy of Wuttichai Tatong's 87th-minute winner.
Bottom side TTM Chiangmai put in a spirited display at home to Chainat but ultimately fell to a 3-2 defeat.
Goals from Phuwadon Suwannachat and Kendall Jagdeosingh handed the visitors a two-goal lead at the break, but Chiangmai pulled one back through Brazilian striker Leo on the hour mark.
Lee Dong-won added a third for Chainat in the 62nd minute but Leo grabbed his second four minutes later to set up a nervy finish, although the Hornbills were able to hold on to the win.
Finally, Santi Chaiyaphauk scored the only goal of the game in the 49th minute to hand TOT a 1-0 triumph at Chiangrai United.
Sunday's Thai Premier League Results
TTM Chiangmai 2-3 Chainat
Chiangrai United 0-1 TOT
Samut Songkhram 3-2 Bangkok Glass
BEC Tero Sasana 0-2 Thai Port
Police United 0-1 Esan United