Goals from Fraizer Campbell, Joe Mason and a Peter Whittingham penalty secured three valuable points for the Bluebirds.
Cardiff now lie 11 points clear of third-placed Watford, who face Hull at the KC Stadium on Tuesday.
It was a performance which left Mackay beaming with delight.
He said: "I'm absolutely delighted with the position we're in and this win gives us that little gap with seven games to go.
"I've a group who have been up there for four months to be analysed, criticised, shot at, ignored and studied, but we have stayed in the top position. We have shown a great character and mentality within our team.
"We are fighting every inch to make sure we give our supporters the dream they want.
"The performance and result was very pleasing. We started really well and we were relentless. We looked like a team that dominated from start to finish. That doesn't happen too many weeks in this division."