Summer recruit James Keatings stole the show at Stark's Park with the Tynecastle outfit's first hat-trick on the road in 15 years, before substitute Gary Oliver added a late fourth goal.
The interchanging of the Gorgie side's pacy attacking quartet, backed by the solidity and calmness of Morgaro Gomis and Prince Buaben, was too much for Raith Rovers, who had won their first two games. "We need to be relentless and keep winning, keep pushing and pushing," said Hearts head coach Robbie Neilson. "If we have a 100% record 10 games in I'll take that and we'll talk from there. We've done it so far but there's still a long, long way to go."
Hearts surged ahead 12 minutes in and never looked back. A hesitant Kevin Cuthbert was tempted off his line but was beaten to a chipped pass by Billy King.
Sam Nicholson looked to have scored with a back-heel from the winger's cutback but with the linesman keeping his flag down as Jason Thomson intervened on the line, Keatings was on hand to gleefully hammer in.
King was involved again in the second, with a wonderfully direct run from the halfway line in the 28th minute. His shot was blocked and Buaben's drive ricocheted off Cuthbert's chest but Keatings forced the ball home.
Keatings' hat-trick came with 57 minutes gone when he curled a free-kick up and round the Raith wall and beyond the dive of Cuthbert.
Oliver got in on the act in the 90th minute when he pounced on a loose ball to clinically slide home .
"It was a sore one to take, especially at home," admitted Raith manager Grant Murray. "We made a mistake for every goal and Hearts were lethal. They punished us at every opportunity and showed their class."