Atletico won 1-0 on Tuesday night to take the lead in their round of 16 Champions League tie.
Saul admits their relentless work off the ball was key to the victory: "It is the result of work, not to stop believing, persisting, continuing to work. Although the world does not believe in us, we continue to work side by side and have done an immense job.
"We have done a very good job, it was working to be together.
"They have very fast players up top, Firmino leaves room for Mané and Salah and we had to be together without leaving them on the wings."
He added: "Many people want to kill us, they criticise us a lot but the Atletico people are really in the good times and in the bad times and we have to show them that gratitude on the field."