Pressure on Philippe Clement intensified following the dismal home Scottish Gas Scottish Cup defeat to Championship side Queen's Park last Sunday and his side got a break in the 20th minute when defender McCart could do little about putting the ball into his own net from a Ianis Hagi cross.
At the other end, Cerny curled a shot from the edge of the box inches wide of Gordon's right-hand side but he made no mistake when Igamane's drive came off Adam Forrester and into his path, dispatching the ball past Gordon - with the home fans still complaining about a penalty appeal ignored seconds earlier when Gers defender Nsiala clashed with James Wilson inside the box.
As Hearts came back again, Butland made further saves from Steinwender, Kabangu and substitute Sander Kartume but McCart again put the ball into his own net, trying to thwart Gers substitute Cyriel Dessers latching on to a Hagi pass.
Hearts almost took the lead in the 17th minute when Kabangu, the 27-year-old on loan from Belgian club Union St Gilloise, was able to fire off a shot from 14 yards but Butland made a crucial save and the visitors survived.
However, Czech winger Vaclav Cerny restored the visitors' lead in the 61st minute and McCart, who signed from Rotherham at the start of January, put into his own net again 12 minutes later to cut Celtic's lead over the Light Blues at the top of the league to 13 points.
