Muang Thong United coach Mario Gjurovski said there are still several things his team have to improve after the Kirins beat Chonburi 1-0 in Thai League 1 on Sunday night.
Visiting Muang Thong were reduced to 10 men in the 68th minute when Willian Popp was sent off for a second bookable offence.
However, Muang Thong captain Suporn Pinakatapho scored the winner with a superb long-range shot after 74 minutes.
After 20 matches, the Sharks are third on 36 points, 16 behind leaders Buriram United.
Muang Thong are ninth on 26 points.
"I am very happy that we won but there are several problems that we have to solve," said Gjurovski.
"Credit to our players particularly Suporn. Normally, he prefers crossing the ball but I told him to attempt more shooting and it worked."
Chonburi coach Sasom Pobprasert said his players' fitness levels were below par, adding: "We made mistakes and were punished. We have to bounce back in the next game. I hope my players' fitness will be good for the next match."
Chonburi will next visit Nongbua Pitchaya on Sunday, while Muang Thong will host BG Pathum United on Saturday.
In another game on Sunday night, Lumphun drew 0-0 with Nakhon Ratchasima.