Spurs visit the Cardiff City Stadium on Sunday and Mackay believes the Gareth Bale sale has enabled Andre Villas Boas to revamp his side enough to push them into the top four.
The Bluebirds beat Manchester City at home earlier this season and are now facing another of the top sides as they settle in to Premier League life.
Mackay is confident that his side can give Spurs a game but the former centre half knows that Tottenham now have the quality to become a top four side.
“Because of the extra amount of the money the Bale deal actually made for the club, their squad… looks like a Champions League squad,” said Mackay.
“Spurs went out and brought all those players in and then eventually did the [Bale] deal.
“It looks as if it has been very good business,” said Mackay.
“The players that they brought in – everyone in football knew in football they were top talents that were on the market and they were going to cost a lot of money
“It was a top six Premier League squad but… they have gone and strengthened in depth and some of the players they have got I really covet.”
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