Mirco Antenucci and Chris Wood struck in the space of two minutes in first-half stoppage time as Leeds snatched control and - after Town had threatened to get back in the game early in the second period - Mowatt fired a spectacular third for the visitors.
Mowatt's goal was a carbon copy of the long-range effort that had sunk Cardiff four days earlier and left Town staring at defeat.
"I told the players at half-time that Huddersfield will come out and have a go," Evans said. "But we had to remain patient and keep our shape and if we break we break with pace and power.
"I couldn't have painted a better picture and it opened up to a special young man who's once again scored a special goal.
"It was a stunning strike but he does it in training most days.
"It's not just his two goals but his all-round play. (There were) Periods in the second half when he kept the ball and worked hard and was smart and it makes the babies like him and (Lewis) Cook very special."
The visitors should have been reduced to 10 men in first-half stoppage time when Scott Wootton escaped a second booking for his foul on Town substitute Emyr Huws and Evans admitted he thought the defender was lucky to stay on the pitch.
"Yes I did," the former Rotherham boss said. "We gave the ball away cheaply and I think it was Cook that won the second ball and Scott lunges into the challenge.
"I think more and more you see referees try to manage those situations, but I wouldn't have been surprised if he had got a second yellow."
Town will consider themselves unlucky to be on the wrong end of such a scoreline and new head coach David Wagner, watching from the stands and set to start on Monday, will have been pleased his players did not fold.
"The performance was good," said Huddersfield academy boss Mark Lillis, who stepped in as Town caretaker for the fourth time following the sacking of Chris Powell on Wednesday.
"I was pleased with the way we went about the second half as well. We showed bravery.
"I said to them at half-time when they were having a moan about the sending off, we can't control that....(the referee) has made the decision.
"Anywhere else on the field, he had been booked and it would have been a booking, but I'm not going to touch on that.
"Their third goal was a fantastic goal but we kept going right to the end."
Lillis confirmed young Danish midfielder Philip Billing, making his full home debut, was forced off in the first half with a foot injury.
Leeds skipper Liam Cooper had earlier been stretchered off after colliding with team-mate Wootton.