Gomes took time to adapt to the Premier League when he arrived from PSV Eindhoven at the start of the last campaign.
Helped by goalkeeping coach Tony Parks, Gomes has been consistent this season and on Wednesday evening produced a string of saves to inspire a famous win over rivals Arsenal and keep Spurs in the hunt for a Champions League place.
"He's up there with the very best," Redknapp said. "When he came here Tony Adams, who had worked in Holland, said they'd signed the best goalkeeper in the world.
"I watch Dutch football on TV and it's a completely different game and it took him time to adjust. He's had a couple of dicky moments but ever since then he has got better and better and some of the saves on Wednesday, particularly a couple from Robin van Persie and from Sol Campbell were vital saves."
His performance against Arsenal could not have been further from his displays when Redknapp first took over.
The Spurs boss said: "I always knew he had the ability. I spoke to Guus Hiddink and he said he nearly took them to a Champions League final in 2005, he's that good."