Kranjcar has played four Premier League games in a row - his longest run since joining from Hadjuk Split in August last year.
Redknapp said: "Niko's getting better all the time. He's a good footballer who has great control under pressure. He's a boy with a big future."
Kranjcar said: "I'm a lot more confident this season. Even the best players in the world can take time to adapt to the Premier League."