The Steelmen fell to a surprising 3-0 defeat at home to Ross County last weekend but they returned to form with a 2-1 midweek win over Celtic before seeing off the Jambos.
A Michael Higdon a strike and an own goal from Dylan McGowan gave them a 2-0 advantage and they held on for all three points despite their former striker John Sutton pulling a goal back for the home side.
"It was a big result because it was probably the lowest I felt last Saturday, it just shows you the highs and low of football," said McCall.
"We've bounced back, two gritty performances as much as anything and the table looks a little bit rosier now.
"All managers ask for a good start, it was important to start well. With Lockie (Gary Locke) in charge (of Hearts), I knew the crowd would be up for it.
"I was delighted with the start and then the pitch began to cut up. We played some good football and we knew it was always going to be a battle in the second half.
"Coming in 2-0 at half-time was great. They scored and they put a lot of balls in the box but we stood firm."