The build-up to Saturday's Premier League home clash was overshadowed by a row over player bonuses that the squad will be entitled to come the end of the season.
Mackay did not want to get involved in the wrangle and says the matter is in the hands of the club's hierarchy.
"They (players) deal with the football club and the chief executive," Mackay told Wales Online. "That's something that can't really come under my brief."
Asked if the stories had an effect on the result against Newcastle, Mackay added: "No. It's certainly not an excuse our players are giving."