The Premier League new boys have broken their club transfer record to land the Danish striker from FC Copenhagen in an £8.5million deal.
It took some effort on their part to get a transfer over the line, with a number of sides expressing an interest in the talented 20-year-old.
Macaky claims three top-flight rivals, and sides across Europe, were also in the running for a player Cardiff hope will get the goals to cement their standing among the elite.
He said: "Cornelius has great potential and is a very good capture for the club.
"We tracked him all last year. But by Christmas, he was in such good form we really didn't think we had much chance because top clubs in Europe were watching.
"We were in competition internationally with another club and then three Premier League clubs moved in to try and take him as well.
"But we were able to do things quickly and I have to give a special mention to Copenhagen. They were tremendous - efficient, professional and friendly."