The club's owner has become so apt that it is almost as though he gets regular practice by tossing darts at a picture of the Scot that Tan has hung in his office. The Malaysian businessman did not miss yesterday, blaming Mackay for Cardiff's relegation from the Barclays Premier League.
A defeat by Newcastle United earlier this month had consigned the Welsh club to the bottom three, a fate overseen by Ole Gunnar Solskjaer. Tan has since claimed that it was brought about by Mackay, who he sacked as manager in December.
The Scottish coach - who has been linked to the vacancy at West Bromwich Albion - last week settled his legal case against his dismissal, but his erstwhile employer has not been sated. Instead Tan claims that it is Mackay rather than Solskjaer who should take responsibility for Cardiff dropping back into the Sky Bet Championship after just one season.
"Why wouldn't you blame him for relegation? He took this club to the Championship," said Tan. "If I had not invested, he couldn't have [won promotion]. Why didn't he earn promotion with Watford? He was their manager for two years, finishing 14th and then maybe 16th.
"When Dave Jones was here, he took us to the play-offs. Malky Mackay came here as a non-performer at Watford and I gave him £15 million to spend. I say the fans must be asked to use their heads and brains to think, not make decisions from the heart. Sometimes, when you make decisions from the heart, you don't think straight."
Mackay had been in charge at the Welsh club for two and a half years when he was sacked after a defeat by Southampton, with supporters often heard chanting his name in the weeks that followed.
At the time, City were a point clear of the drop zone, although owner and manager had been embroiled in a very public row during the weeks which preceded the manager's exit. Tan remains unrepentant and once again admonished Mackay's transfer dealings, in particular the deal which brought Danish striker Andreas Cornelius to the club in the summer.
"We were supposed to have a main striker and we signed a 20-year-old, paying him £45,000 a week," added the owner. "We paid over £10 million. And, guess what? He hardly started. And people ask why I am angry?"