We travel to the Valley just four days after a goalless draw against Alan Curbishley’s men in the Premiership at the Lane. The prize for winning the fourth round encounter is a home tie against Stockport County for a place in the quarter-finals.
Midfield marauder Freund stated: "I think this game is the most important game for now and for the rest of the season. My feeling is that if we can win away at Charlton we then have a good chance to go to the final.
"Everyone knows it is an important year for Tottenham in the FA Cup and I hope we can win at Charlton. If we have a draw and a replay at home, that is also okay. But we can’t lose this game."
Freund says we have to improve on Saturday’s display. He added: "It was a very close game and we were disappointed with the result and our first half performance.
"We were better in the second half and with a little luck we could have won the game but don’t forget that Charlton had the best chance and I think a draw was okay in the end. We have to play better in the FA Cup."
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Steffen Freund has no doubts as to the importance of Wednesday’s FA Cup tie at Charlton.