The Championship side defeated Spurs 2-1 at Elland Road in the fourth round of the competition.
"It was difficult always trying to chase the game," the Tottenham manager told reporters. "We had a good 15 minutes at the beginning when we could have perhaps done a little better with our opportunities.
"We always had to chase the game at 1-0 and then 2-0 made it even more difficult. The players did extremely well to come back into the game at 2-1, but we couldn't create as many opportunities as we normally do.
"That was down to Leeds and how they set up, they got into our faces and made it difficult for us, so credit for them for being so competitive. We didn't have a lot of space, maybe more in the first half and less in the second because they gained inspiration from going 2-0 up."
Tottenham will take on Norwich City away from home in the Premier League on Wednesday.