Mackay says Spurs boss Andre Villas-Boas made a number of quality additions to his squad to offset the loss of the Wales international.
Christian Eriksen, Erik Lamela, Roberto Soldado, Paulinho, Etienne Capoue and Nacer Chadli are among the new faces recruited in spending a summer outlay of over £100million by the north Londoners.
Mackay said: "The talk all summer was that the Bale deal was happening, but Spurs went out and brought all those players in and then eventually did the deal.
"It looks to be very good business. Everyone knew in football that the players they brought in were top talents who were on the market.
"They were all going to cost quite a lot of money, but the extraordinary money that the Bale deal actually made for the club meant they were able to go and do that.
"It looks like a Champions League squad now, it is absolutely a match for the likes of Manchester United, Manchester City and Chelsea.
"The players he already had were a good top-six team, but I think they have strength in depth with the players they have brought in. Some of those players I covet."
Portuguese Villas-Boas has complained about fixture congestion ahead of their trip to face the Bluebirds at Cardiff City Stadium, bemoaning the fact his side will play three games in six days.
But Mackay feels his opposite number would have a different perspective had he managed in the league below.
"They should join the Championship," added the Scot. "We had to cope with that every week. It is something we are used to as in the league we were in it was a regular occurrence in terms of fixture pile-up and the games you have got in a short space of time.
"It is something you have to deal with and the size of your squad helps. I have got great staff here that organise the logistics, when we travel, where we stay, who plays, how we recover, and the structure going into the next game.
"It is something you have to deal with. "But I don't doubt they will be firing on all cylinders on Sunday. The Premier League is the be all and end all for them.
"Spurs' agenda this year, I am sure, is to be a Champions League team. They may have a big fixture list, but they also have a big squad full of quality.
"I have no doubt we are preparing to face a team who are up for it and packed full of quality."