Dennis Murillo's late goal helped hosts Chonburi edge 10-man Port 3-2 in a five-goal thriller in Thai League 1 on Sunday night.
Port's hopes of stealing a point were dashed when Adisak Kraisorn was sent off in the 68th minute.
Yoo Byung-Soo's two early goals for the Sharks were cancelled out by Port's Nurul Sriyankem and Philip Roller before Murillo netted the winner in the 78th minute.
In another game last night, PT Prachuap beat Nakhon Ratchasima 3-2.
Bangkok United's bid to catch up with league leaders Buriram United suffered another blow on Saturday night when they lost 1-0 away at promoted Nongbua Pitchaya.
The winning goal came in the 82nd minute when Thitiphan Puangchan committed a handball and the match referee pointed to the penalty spot following a tip-off from the VAR officials. Hamilton Soares converted the penalty.
The visitors tied the goal during the five minutes injury time but the VAR officials ruled that Suphan Thongsong had scored from an off-side position.
