Visitors Kilmarnock came into the Scottish Premiership encounter knowing a point would lift them out of the relegation play-off berth and above Ross County on goal difference.
Instead they were given a hammering by a Hearts side whose drop to the Championship has already been confirmed, and Kilmarnock fans will fear they may join Gary Locke's men after the one-sided defeat.
Stevenson was the star of the show for the home side, firing his team in front from an 11th-minute free-kick before doubling his tally 13 minutes later when picked out by Sam Nicholson.
The 29-year-old completed his treble in first-half stoppage time, exchanging passes with Billy King before rifling home to leave the visitors shell-shocked at the interval.
Stevenson turned provider 11 minutes into the second half, as King coolly finished, before Callum Paterson benefited from more Stevenson service on the hour to round off the scoring.
It was the first time Hearts had scored five in a game since a 5-1 demolition of fierce rivals Hibernian in the Scottish Cup final two years ago.
