The 33-year-old netted the only goal in the victory over Leicester last weekend before grabbing two assists and being voted the fans' man of the match as they beat Crystal Palace 2-1 on Boxing Day.
And after his sixth start since returning from injury Mackay was full of praise for the former Liverpool man.
"He has had injuries twice this season and he is now getting into a rhythm," Mackay said.
"I know he is a fantastic worker and you saw him in the last ten minutes on Wednesday the way he closed down the full-back and was blocking balls 40 yards from goal.
"Certainly in the attacking side of things and being a threat going forward he is really starting to hit his stride which is obviously pleasing."
The Bluebirds host Millwall on Saturday before a trip to face Birmingham on New Year's Day but the Cardiff chief will not be treating Bellamy any differently than the rest of his squad during the busy festive period.
"Like any of our senior players the medical team manage them slightly differently at times," he said.
"And there will be days when they are on the grass and days when they are of their feet doing something different. He is no different than guys like Heidar Helguson."