Ten-man Lamphun Warriors suffered a 2-1 home defeat at the hands of Uthai Thani on Monday night which left them in a perilous situation in Thai League 1.
Lamphun now have 31 points and have dropped to 13th place in the league table.
The Warriors need to stave off defeats in their two remaining games this season to prevent Chonburi from overtaking them in the race to survive in the top-flight.
Lamphun's late-season dip in form continued on Monday night and the Warriors found it difficult to get going against the impressive visitors.
The hosts were reduced to ten men for almost the entire first half. Oskari Kekkonen was booked for the second time in the match for a foul on Uthai Thani's Aung Thu.
Myanmar striker Aung Thu then grabbed the first goal for the visitors in the 72nd minute before Chigozie Mbah added the second 13 minutes later.
Lamphun's only goal was netted by Siroch Chatthong on 87 minutes.
Uthai Thani coach Jakkapan Punpee said: "We played very well, especially in the first half. We created several chances but could not convert them.
"We changed some tactics for the second half and got two goals. We conceded a late goal but were able to stay focused in the dying moments and take three points from the match."