He told the London Evening Standard: "If we want to become great, the club have to do certain things differently so as to match what the top teams do in a financial sense.
"Since we qualified for the Champions League, we can say, yes, we have become a big team.
"Now, to become like Chelsea or Manchester United, we need to keep the same team for the next couple of years and make everyone happy to stay, rather than being in the situation we were with Luka Modric during the summer.
"There's a lot to be excited about at Spurs now with the new training ground and maybe a new stadium.
"It feels like the future could be really good for the fans but if the players don't stay, we could end up like Aston Villa.
"Not long ago, they were maybe two or three players away from becoming a top team.
"They didn't buy them and they didn't keep the ones who were already there and since that time, they have taken a few steps back.
"Instead of being able to build on what they had, players ended up leaving Villa, so I hope Tottenham will make the right steps."