Bangkok United laboured to a narrow 1-0 victory over Nongbua Pitchaya in their second Thai League 1 match of the nascent season on Saturday night.
A heavy downpour at Pitchaya Stadium left the pitch water-logged, making things difficult for both sides.
Bangkok United dominated the game early but had to wait until the half-hour mark to grab the winning goal through prolific Brazilian forward Heberty Fernandes.
There were a number troubling moments for the Angels but their defenders were up to the task and thwarted the home team's attempts to level the score.
Earlier on Friday night, Buriram United fired on all cylinders in front of a large home crowd as they thrashed promoted Sukhothai 6-1 in their second league match of the season.
Defending Thai League 1 champions Buriram United had goals from Supachai Chaided (nine and 89 minutes), Goran Causic (30), Frank Castaneda (37, 41) and Diego Bardanca (51).
Sukhothai's first goal of the season was scored by Sila Srikampang off a free-kick in the fifth minute of injury time.
After the match, Buriram coach Masatada Ishii said: "This was our first match at our home ground and the way we won it must have made the fans very happy.
"It was a good performance and after we scored two early goals, the players looked confident.
"It's a pity that we conceded a goal at the end of the match and we need to work on that.
"In our next three matches, we face Chonburi, Muang Thong United and BG Pathum United and these all will be difficult games for us.
"We have to work harder and must have varying attacking tactics. We need to improve our defence as well."
The Thunder Castle will next meet Chonburi on Aug 27.
Four more matches are scheduled to be played this evening.