German Grandmaster - Jan Gustafsson threw the 2011 Thai Chess Open in Pattaya wide open by defeating tournament leader Nigel Short of England in the seventh round.
With two rounds of Thailand's richest tournament to play, Gustafsson, seeded third, now shares the lead with top seed Paco Vallejo and the two will meet in a much-awaited penultimate round encounter on Saturday.
Gustafsson was pleased with his win over the former world title challenger but was unsure of the turning point in the game; "I think he didn't have time for his [slow plan from moves 17-20]. His piece sacrifice at the end [isn't great] but I already have strong threats."
Vallejo joined Gustafsson at the top of the standings with a tough win over Chinese International Master Yang Kaiqi, with Short and 4 other players half a point off the pace.
However 2010 Thai Open Champion - Sune Berg Hansen is not among them and has no chance of retining his titled after the Danish Grandmaster was forced to lower his colours to unfancied Dutchman - Pieter Hopman.
Thailand's top player Wisuwat Teerapabpaisit moved into prizemoney contention with an upset win over Russian International Master Alexey Romanov. Teerapabpaisit is now only a point behind the two leaders. 15-year-old Warot Kananub also continued to impress and retains chances for his first International Master result.