A couple of major upsets in Thai League 1 on Sunday night saw PT Prachuap settle for second spot and former champions SCG Muang Thong United tumble to 10th place in the table.
Prachuap, who sat on top of the league standings before the weekend games, fell 3-2 to hosts Chonburi following an exciting duel.
Defending champions Buriram United, who held off a late fightback by Samut Prakarn City to win 3-2 on Saturday night, have now taken over the top spot for the first time this season and enjoy a two-point advantage on Prachuap.
Ratchaburi gave their new coach Marco Simone, a former AC Milan and Italy star, a perfect start as they defeated Muang Thong, a side loaded with former and current Thai national team players, 2-0 at home.
In Chonburi, the Sharks were cruising towards a cosy win after netting goals through Zaw Min Tun and Lukian Almeida early in the first half, but Prachuap fought back after the break.
The visitors equalised as Herlison Caion and Adul Muensamarn found the net, but Lukian headed home a Si Thu Aung cross in the last minute to give bottom-placed Chonburi their first victory of the season.
Ratchaburi got going in the second half when Yannick Boli struck in the 49th minute, giving a large home crowd something to cheer about. Kang Soo-Il then fired home a rebound from near the top of the box to make it 2-0 for the hosts.
The Kirins, despite spending heavily in the close season, have yet to prove their title credentials, reeling in the bottom half of the table with just six points from five games so far.
In another shock result, Lonsana Doumbouya had a brace as newcomers Trat routed top-flight long-timers Suphanburi 4-0 at home.
The other scorers for Trat were Bireme Diouf and Adefolarin Durosinmi.
Visiting PTT Rayong meanwhile beat Chainat 2-1 for their second win of the season.
