BG Pathum United coach Aurelio Vidmar and Port boss Dusit Chalermsan have a point to prove at their new clubs in the 2021/22 Thai League 1 campaign.
The new season kicked off on Friday night with promoted club Nongbua Pitchaya beating Nakhon Ratchasima 2-0 in a northeastern derby.
In their first ever match in the top flight, the Gamecocks sealed the win over the Swat Cats thanks to Brazilian forward Hamilton Soares' goals after 39 and 43 minutes at Pitchaya Stadium.
Australian Vidmar, 54, succeeds Dusit who quit Pathum after steering them to their first ever title under the current name last season.
Dusit, 51, has since returned to Port.
Vidmar coached the Rabbits when they were known as Bangkok Glass from 2016-2017.
The former Australia international has previously coached his country's senior team as well as U20 and U23 sides.
He was coach of Singapore's Lion City Sailors before making a return to BG.
The Aussie has enjoyed a good start to his second spell at the reigning Thai champions.
He guided them to reach the knockout stage of the AFC Champions League.
The Rabbits also won the Thailand Champions Cup, the season curtain-raising match, beating FA Cup winners Chiang Rai United 1-0 on Wednesday.
"The win boosts our confidence ahead of the new season," Vidmar said after the game.
BG, considered favourites to claim their second successive T1 crown this term, travel to Chonburi for their season opener tomorrow.
Former Thailand international Dusit left Pathum as he was reportedly upset by the club's plan to move him upstairs to open the way for Vidmar.
He joined Thai League 2 side Rajpracha before returning to Port, who finished third in T1 last season, after being approached by club chairwoman Nualphan Lamsam.
His appointment came after Port were eliminated in the ACL group stage leading to coach Sarawut Treephan getting a new role as technical adviser.
Nualphan is confident that Dusit is capable of taking Port to reach their target.
Port will open their season at home to Police Tero on Sunday.
The Klong Toey-based club will be out for revenge against Police who beat them twice last term.
Buriram United, who were runners-up last season, and True Bangkok United begin their campaigns on Saturday.
Buriram should have few problems when they host Suphanburi, while Bangkok United travel to newcomers Chiangmai.
Buriram and Bangkok United are among title contenders.
PT Prachuap also face SCG Muang Thong United on Saturday.
It will be Masami Taki's first competitive game as coach of Prachuap.
Both Taki and Muang Thong boss Mario Gjurovski are looking forward to a good start to the season.