The Bluebirds boss described his team as "fantastic" and singled out two-goal hero Fraizer Campbell for plaudits.
"They were fantastic to a man, disciplined, did their job today and deservedly won the game," Mackay told Sky Sports News.
"We worked hard on our set-pieces and we have got good players in there that can aggressively attack the ball as long as the ball comes in with quality and Frazier's like that.
"We had good movement and fantastic crosses coming in and that is something that is difficult to defend for anyone."
"We were playing against top, top players. I've spoken to the boys about how proud they should be because they deserve to be here and they deserve to be out there playing against these top players and it is about belief and believing in your own ability," Mackay added.
"I thought tactically the players out there did an incredible job today and deservedly won the game."
The result marks Cardiff's first win since their long-awaited return to the English top flight.