The Premier League side made sure their hopes of qualifying to the next round of the competition remained alive with a comprehensive performance at the Tottenham Hotspur Stadium.
A first half double from Carlos Vinicius coupled with second half strikes from Harry Winks and Lucas Moura were enough to send the Bulgarian outfit home with their tail between their legs.
Mourinho was happy his men tamed Ludogorets despite making changes to his usual lineup.
"It was important. There is a risk of every team on six points against them. If that happens to qualify you need a lot of points. Normally nine points would be job done but it is not job done,” the Portuguese said.
"You need a result but today was important. We made lots of changes but it was important to take it seriously, it was good.”
"The games are important, every game is important. We don't look to certain competitions, we look game after game. To play all the same players is not good for the condition and for the mentality of those who play."
"I am happy for them, some players had really nice performances,” Mourinho replied when asked about the youngsters he fielded.
“Japhet Tanganga had his first match after long injury, nice chance for the kids to make history. 4-0 and three points, that's good.
"I know the kids well. Harvey White works with us every day in our squad, same as Jack Clarke, Dane Scarlett did pre-season with us. We know what they can do but it has to be the right moment and today was the right pressure for them."
Next up for Mourinho and Tottenham is a daunting trip to face Chelsea at Stamford Bridge in the Premier League on Sunday.
