Thistle had lost their last five matches to precipitate an alarming slide down the table, prompting demands for greater defensive resolution from manager Alan Archibald, and his side duly delivered as they confidently subdued a lacklustre United side, who have not won in four games.
Kallum Higginbotham was sent racing clear early on but his progress was halted by the assistant’s flag, much to the consternation of the Thistle bench.
Nadir Ciftci then fluffed his lines six yards out after Fojut had put himself about to good effect at a corner kick before Lyle Taylor broke free but could not find a way past Radoslaw Cierzniek.
Thistle forged a head with a goal of genuine quality (34) as Stephen O’Donnell produced a sweet finish after a clever flick from Taylor.
Four minutes before the half-time whistle, Higginbotham swung in a corner and defender Fojut diverted the ball into his own net under pressure from Frederic Frans.
United had failed to test Paul Gallacher in the Partick goal during the opening half and the mood of the home support did not improve during a dour second period, devoid of graft or guile as the flow of play was punctuated by a series of injury stoppages.
Stuart Bannigan went close for Thistle with a low shot from 16 yards while United’s frustration was summed up when Mario Bilate picked out Henri Anier in a great position 10 yards only for the Estonia striker to produce a miserable finish.