Modric spent four years at Tottenham between 2008 and 2012 before joining Real Madrid.
The Croatia superstar has helped Real win the Champions League in four of the last five seasons and reached the World Cup final in the summer.
Modric and Croatia knocked England out at the semi-final stage and Redknapp says the 33-year-old is a very difficult player for opposition teams to stop.
And he has paid tribute to his time at Tottenham, saying it had a big influence on his career.
“Before the semi-final you try to get a plan in your head about how you stop certain players,” Redknapp said on Sky Sports.
“There’s certain players that you have to respect that are so good on the ball.
“The way that they manipulate it, the way that they touch it, the way they receive it, whether they pop it off first time or play a long pass. And he’s one of those.
“You just have to do your best to stop him as much as you can.
“If you let him have time on the ball, there aren’t many better.
“He’s the best player in the world right now, he’s been voted by everybody.
“I remember when he first arrived at Tottenham and he struggled a bit, I think the physicality of the Premier League.
“Obviously going to Real Madrid and playing with great players has helped him.
“But I think playing in the Premier League have him a massive appreciation of how you have to be so fast on the ball and the development of how much he improved at Tottenham was amazing.
“Now I see a player and he’s such a nice guy as well, an unassuming superstar if you like.
“He deserves all the plaudits he’s getting right now.”