Promoted Nakhon Ratchasima produced the first major upset of the nascent Thai League 1 season on Sunday night when they shocked former champions Muang Thong United 2-1 at home.
Siam Yapp put the hosts ahead in the 13th minute before Muang Thong United equalised through a goal by Poramet Arjvilai in the 50th minute.
Four minutes later the Swat Cats' Greg Houla fired a shot straight at Muang Thong goalkeeper Kittipong Phutaechuek, who let the ball slip through his hands and allowed Nakhon Ratchasima to walk away with three points from their first game of the season.
Nakhon Ratchasima coach Teerasak Pho-on praised his team's defenders after the match.
"It was a good game from both teams. We started off well and got an early goal from Siam Yapp, but after that Muang Thong improved and had several chances to equalise but we did well in defence," said Teerasak.
"In the second half, Muang Thong did tie the score but we got lucky with that shot only four minutes after conceding the equaliser.
"But it is always good to start a season with a victory and we are happy with the result tonight."
Meanwhile, Ratchaburi started their campaign with a 3-2 home defeat at the hands of Nakhon Pathom United.
Tatsuya Tanaka found the net in the 15th minute and gave the Dragons a 1-0 advantage which the home team retained until the break.
In the second half, Nakhon Pathom came back strong and fired home three goals through Nopphakao Prachoklang in the 48th minute, Taku Ito (56) and Valdo (65).
Ratchaburi scored their second goal through Kiatisak Jiamudom two minutes before time but it was too late to start a recovery.
Also on Sunday night, Lamphun Warriors had a good opener as they edged Uthai Thani 1-0 at home.
Anan Yodsangwal scored the winning goal in the seventh minute to help the Warriors pick up three points from the match.