Chiang Rai United celebrate with the Thai League 1 trophy on Saturday night.

Following a dramatic turn of events in the very late stage of the final-day matches, Chiang Rai United were crowned the winners of Thai League 1 for the first time in the club's history on Saturday night.

Defending champions Buriram United seemed heading for a seventh league crown but an 87th-minute header by Caique denied them the victory at Chiangmai, who became the first of the three teams to be relegated last week.

Chiang Rai United celebrate their first Thai Leauge 1 champions tropy.

The Beetles, on their part, went on a goal-scoring rampage at Suphanburi, thrashing the 10-man home team 5-2.

Both Chiang Rai United and the Thunder Castle ended up with identical 58 points from 30 matches. However, the Beetles were declared the winners of the league on the basis of a better head-to-head record.

Chiang Rai held Buriram to a goalless draw away in the first leg in April and then thrashed the northeastern giants 4-0 at home in July.

Chiang Rai needed a jolt before they got going on Saturday night.

Thanasit Siriphala pounced on a mistake by Chiang Rai's Shinnaphat Leeaoh and set up Cleiton Silva to score near the 15-minute mark.

The Beetles, who knew they needed a victory to have any chance of winning the coveted league crown, went all out on attack but needed almost half an hour to get level. Siwakorn Tiatrakul equalised for the visitors.

Chiang Rai went ahead early in the second half when William Henrique found the net and soon Ekanit Panya made it 3-1.

Thanasit pulled one back for Suphanburi but Chiang Rai widened the gap again when Bill Rosimar converted a 72nd-minute penalty.

Their fifth goal of the night was claimed by Phitiwat Sukjitthammakul late in the match.

Suphanburi's fate in the top tier now hangs in the balance. In case PTT Rayong decide to continue playing in Thai League 1, Suphanburi will be relegated to the second division.

Buriram United are denied a victory by Chiangmai

Buriram looked the better side for the most part of the first half but their lack of clinical finishing was exposed by a determined Chiangmai defence.

Nacer Barazite delivered again by putting Buriram ahead early in the second half. They remained on course for another title until three minutes from time when Caique -- on loan from Chiang Rai -- headed home a Atthawit Sukchuay corner to hand the trophy to his parent club.

Chiang Rai are only the third team to win the top flight after Buriram and SCG Muang Thong United since the country's premier tournament was revamped in 2009.

In other matches, True Bangkok United routed PTT Rayong 4-0, Chainat upset Chonburi 2-1, Sukhothai escaped relegation by beating Nakhon Ratchasima 4-2, Port and Samut Prakan City played out a 2-2 draw, Prachuap were held 2-2 at home by Ratchaburi, and Muang Thong edged Trat 4-3.