The 19-year-old, on loan from Sporting Lisbon, scored the only goal in the shock victory with a fourth-minute header and, despite the muddy White Hart Lane pitch, displayed his skills for more than hour.
"I took a gamble with him because he's been doing things in training that would blow your brains out," said Redknapp.
"He has a left foot like a magic wand and all the other players have been totally impressed with him since he arrived. They were not really the right conditions for him at Tottenham, but when he gets a decent surface to play on I believe you are going to see something really special from him."
Sadly, that will not happen when West Ham go to Grimsby tonight in a testing FA Cup fourth-round replay, even if the First Division club's ground is in perfect shape. Neither Dani nor West Ham's Croatian centre- back, Slaven Bilic, who also made an impressive debut at Spurs, are eligible to play in the game and Redknapp must reshape the side after three Premiership wins in a row.
Tony Cottee, the top scorer who was relegated to substitute against Tottenham but carved out enough chances to have scored a hat-trick after replacing the tiring Dani after 66 minutes, is set to reclaim his place with Adrian Whitbread likely to deputise for Bilic.
"It is a shame we've got to make the changes because it will be a tough job at Grimsby and I would have liked to have kept Bilic and Marc Rieper together at the back as they looked really solid," said Redknapp.
There will be plenty of chances for the West Ham manager to put his new boys through their paces, though, as they have two more London derbies - against Chelsea and Arsenal - within the next 11 days.
There is a fifth-round cup tie as well - also against Chelsea, if they beat Grimsby - and a visit from the League leaders, Newcastle, to follow.
Redknapp could now field a complete team of non-Englishmen if he chose to do so, but is still desperate to add the Romanian Ilie Dumitrescu to his ranks.
The World Cup player's pounds 1.5m move from Spurs is currently blocked, however, by the Department of Employment's refusal to renew his British work permit and Redknapp insisted: "It will be criminal if our appeal against that decision is not upheld. I've had the boy in tears and he tells me he has not slept for four nights. It is a terrible shame because he and his family face being kicked out of the country if the permit is not granted.
"It is concerning me more than just worrying about West Ham and money. If we can we'll take a gamble and tell the authorities we'll accept a permit just for the rest of the season, pay Tottenham their fee and then prove that we want him to play in all our matches."Reuse content