 In 2012,
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Muangthong engaged an unbeaten run which lasted the whole season, and Teerasil also scored four goals in a single match, an 8–1 routing over BBCU on 18 October.Ten days later he scored in a 2–2 draw against BEC Tero, a goal which granted the title, took his tally to 24 goals and broke the previous record of Ronnachai Sayomchai in 1998 (23 goals).After his impressive goal tally in the season, Teerasil was invited by La Liga sides Atlético Madrid and Getafe for a trial, but as the former was a Muangthong partner, he headed to Atlético Madrid in January 2013; he also attracted interest of Trabzonspor in June.