Spurs looked destined for a place in the final 16 as they led the League One side 2-1 at White Hart Lane on Saturday evening but a stoppage time goal from a Jermaine Beckford penalty earned Leeds a replay at Elland Road.
"We won't dwell on it. It's one of those things," Redknapp said after the match.
"I'm disappointed tonight because we threw the game away when we had it in the bag.
It didn't happen, though, so you have to pick yourself up and go again Tuesday (against Fulham). That's football, what can we do?"