The attacker was thrilled with his side's scintillating return to form against the Bhoys and had nothing but praise for Neymar following the Brazilian's sensational hat-trick
The Blaugrana had been struggling in recent weeks, with back-to-back defeats against Ajax and Athletic Bilbao having piled the pressure on both the players and coach Gerardo Martino.
Consequently, Tello was pleased with Barca's scintillating performance against the Scottish champions.
"We've had a slight drop in form but this proves we are over that and looking forward to playing with intensity in the knockout round now," Tello was quoted as saying on the official Uefa website.
"This is just the result and performance we needed. We really got stuck into giving a good performance, very intense from front to back.
"We worked so hard, moved the ball so well and pressed so hard that Celtic didn't have a chance to think. You can see all this in the size of the result."
The 22-year-old attacker then went on to hail Neymar's contribution, with the Brazilian having hit a stunning treble, and praised the summer recruit for having adapted to life at Barcelona perfectly, as well as proving a more than able deputy for the injured Lionel Messi.
"Neymar managed to fill in for Leo very well indeed, but I see no point in putting him under pressure," Tello mused.
"Many people were saying he wasn't in form in front of goal and there's a hat-trick this evening to counter that argument. He's fitted into the team from the very first moment."
Neymar now has netted eight goals in 21 appearances in all competitions for the Blaugrana since joining from Santos.