"It was good to get back home again and obviously get the win, the clean sheet and score two goals," said Mackay.
"I'm delighted. We have lost one goal in three games so it looks like we're sealing it up at the back and also getting on the scoresheet as well."
The three points meant Watford have taken 19 from the last available 24 at Vicarage Road.
Mackay continued: "We've got to make sure that we keep that record going.
"We've got to make sure performance levels are up there and I told them tonight to take their performance from Saturday, because we did well [1-0 defeat at Barnsley] and deserved something out of it.
"I told them take that into tonight and also the game last Tuesday [3-0 win] against Sheffield United and start like that and I think they did."
The Hornets have improved defensively since Taylor's free transfer arrival from Birmingham and his new manager said: "He probably allows Jay DeMerit to not have to be the lead central defender.
"You saw again tonight when they decided to put pressure on that Martin gets his head on an awful lot, he gets into the right areas and he's also comfortable on the ball."
City boss Gary Johnson held his hands up after an abject first-half display by his side.
He said: "I came here to be bold, we came to be bold, and I gave us the shape to be bold with three strikers, but it didn't turn out that way.
"After 25 minutes I realised that wasn't working on the day, or they didn't make it work.
"We were getting bullied a little bit in the first half through clever play. It was good play, it was strong play and Watford's two forwards were lively.
"The second half was really the boys trying to save face and to get stronger with their centre-forwards and they competed a little bit better all over the field.
"There still wasn't an end product on the day, which we're really disappointed with. We were second best on the day."
Watford's early pressure was rewarded in the 14th minute when Adrian Mariappa sent over a fine cross from the right and Helguson pulled off his man to score with a trademark header.
They doubled their lead with a deserved second in the 34th minute.
After Alvaro Saborlo had been booked for a foul on DeMerit, Henri Lansbury struck the resultant free-kick accurately to the back post where Taylor guided home his first Hornets goal from a tight angle on the right side of the six-yard box.
City's best chance of getting back into the game came six minutes after the interval when Liam Fontaine was left totally unmarked to connect with Lee Johnson's free-kick from the right, but England Under-21 goalkeeper Scott Loach superbly tipped his header over.