Spurs travel to Elland Road for the fourth round game, and the assistant manager only ever tasted league victory over Leeds once during his five-year playing spell at White Hart Lane.
During that period Leeds were a successful side, challenging for the Premier League and reaching the UEFA Champions League semi-finals in 2001, a far cry from their current 11th place in the Championship.
Previously Neil Warnock's side spent three years in the third tier, and Freund said: "Yes, of course I'm surprised.
"During my time here as a player we always had difficult games at Elland Road.
"They were a really strong team, they finished in the semi-finals of the Champions League and they are not in the Premier League at the moment.
"That's why it's a surprise for me, but still they have a very strong squad. They beat Southampton and Everton in the League Cup this season.
"They've got nine wins and three defeats at home. It will be a difficult game for us."
Although Spurs are on an eight-match unbeaten run, Andre Villas-Boas' men are still far from certain of a top-four finish, and Freund insists the FA Cup is one of their priorities.
"We take it seriously," he said. "The FA Cup is one of the biggest cups in the world and we do that for every game.
"The FA Cup is massive for Tottenham Hotspur. We've won it eight times and we'd like to do it again."
Freund was keeping his cards close to his chest on Tottenham's pursuit of Schalke midfielder Lewis Holtby.
"At the moment he will be here in the summer," he said. "I can't give you an update, I'm not involved in negotiations about new players."