Tottenham had to work extremely hard to claim a 4-3 victory over League Two Wycombe and at one point of the match, it looked like Spurs would be heading out of the competition after going two goals down.
Spurs put in a terrible performance during the first half of the encounter and manager Pochettino has expressed his disappointment at how his fringe players performed on the day.
The Argentine boss said: "When you sign a player for your squad you need to be available to play and quality enough to play this type of game.
"If you cannot play this type of game, then we have a problem.
"The first half was very difficult. We need to assess why, to analyse. It is true it was the 11 players. It is not only one or another. I wasn't upset.
"It was not a good performance from the beginning but in the second half we scored four goals.
"It's not that we only trust 10 or 11 players because if you want to do win titles, if you want to be in the history of football, it is not only 11 players. Or 14 or 16. It is about 20, 22, 25 players.
"We are building a really good squad to try to go far in every competition but always it is difficult."