On Friday night, Mahrez was drafted into the starting XI at the King Power Stadium for the first time since his prolonged absence from training in the wake of his purported failed move to Manchester City.
The 26-year-old received warm applause from the home supporters when his name was announced before the fifth-round tie, and a standing ovation when he was substituted late on following his assist for Jamie Vardy's winner.
"It's behind us," Puel told Sky Sports News following the win over the Blades. "Riyad came back with high quality and it is a good feeling for us of course.
"It was good support from the fans to Riyad and important to remain a good feeling for the future. I said before it was important to remain united after this situation but it was good in the end to see the good feeling.
"The most important thing was to win the game and to see again Jamie and Riyad play together is a good feeling. Riyad was a little frustrated at the end of the game because he wanted to score, but that is good."
Mahrez has made 167 appearances for Leicester, scoring 44 goals and registering 35 assists.