Slovakian internationalist Robert Tomaschek was back in the Hearts starting line-up after missing a couple of months with a knee injury and marked his return with a goal.
Under bright sunshine, the visitors were first to threaten when Gordon Durie saw a cross from the right deflected towards goal but Stephen Wright hooked the ball clear.
Juanjo forced the game’s first corner when Hasney Aljofree brought his promising run to an end but Steve Fulton’s delivery was easily cleared by the home defence.
With six minutes on the clock, Kevin James had to be alert to intercept a ball over the top from Joachim Fernandez, but two minutes later the Jambos broke the deadlock. Fulton gathered the ball wide on the left before playing a cross into the area. Tomaschek found himself in acres of room some ten yards out and he made no mistake with his header past the stranded Alan Combe.
United had a half chance in the 12th minute when Gustavo Fuentes had an opening but Fulton was alive to the danger and blocked the No.9’s shooting chance with an excellent tackle.
Gordan Petric, playing in the middle of the park, sent Andy Kirk scampering away down the right and his cross was nervously sliced clear.
Tomaschek then found himself booked by referee Stuart Dougal in the 17th minute after his tackle on Fernandez.
With 24 minutes gone Hearts won their second corner and from Juanjo’s cross the visitors doubled their advantage. The Spaniard’s ball in fell to Kirk and the striker’s low shot from 12 yards somehow found its way past Combe and into the back of the net.
Things went from bad to worse for the hosts moments later when Stephen Wright was stretchered off injured with John McQuillan replacing the defender.
Hearts’ afternoon got even better on the half-hour when they went three ahead. Juanjo raced down the right and his cross was rifled home by Kirk from inside the six-yard box.
With 36 minutes gone, the rampant visitors went in search of a fourth goal and Durie was halted on the edge of the box by a good tackle from McQuillan.
Five minutes from the interval Kirk thought he had grabbed a first-half hat-trick when he blasted the ball home but the whistle had already gone for a foul by Petric on Combe.
In a rare United attack, Jamie Buchan drilled a low shot towards goal, Antti Niemi saving low down to his left, although the ball was heading wide in any case. Petric was inches away from adding his name to the scoresheet when his 30-yarder drifted just wide on the stroke of half-time.
United boss Alex Smith made substitutions with Tasso Venetis and Carlos Marcora entering the fray. The move was a bid by Smith to change his side’s fortunes and although they looked brighter in the second period, it was Hearts who came close again when Colin Cameron shot wide.
Durie did have the ball in the net but an offside flag had already been raised. But the boys in maroon made it four goals in the 80th minute when Kevin James headed home.
Hearts: Niemi, James, Murray, Petric, Pressley, Tomaschek, Fulton, Cameron, Durie, Juanjo, Kirk.