The Scottish champions have suffered an uneven start to the season, dropping points in the league, relinquishing their hold of the League Cup and disappointing in Europe.
Speaking at the signing of Venglos' compatriot, Lubomir Moravcik, 33, a pounds 300,000 buy from Duisberg who has spent much of his career in France, McCann welcomed the new midfielder but he was keen to assert the modest outlay was only the beginning of a much-needed investment in the playing resources.
"I think big names always come second to team performances," he said, "but I can assure you we do intend to bring quality assets into the team. That will cost money but it will be spent.
"There has been frustration by our fans, myself included, that we have not been able to make changes as quickly as we would like but we want the right kind of players.
"Jozef Venglos has told us his plans for the team, we have done our research and we are pursuing players. He has identified the areas we need to strengthen."
Venglos made it clear that despite the long-standing association between the pair - he gave Moravcik his first of 74 international caps - there will be no special treatment. "Probably he will have more criticism from me, but no, I will not look after him more than any other player, it will not be like that. The truth will be seen on the pitch," he said.
Celtic have a highest number of season tickets in Britain, around 52,000 in their 60,000-capacity stadium, but McCann is keen to place into context how much money this generates.
"The majority of fans realise the season ticket money is not the transfer fund, it does not even equal the wage bill, yet there is no question we try to deliver value," he said.
"The average that all our season tickets bring in is pounds 10 per person, but we recognise it is up to us to provide quality players, we are building so we can afford the best."Reuse content