Germany international Neuer produced inspired form during the final stages of the tournament in Lisbon, appearing back at the very top of his game after a couple of years struggling for form and fitness.
Parisian winger Kingsley Coman proved Bayern's match-winner but Tuchel had no doubt over how decisive his compatriot Neuer proved at the other end of the field.
"That is, of course, a bit of a distortion of competition," Tuchel said. "We also have [Keylor] Navas, but Neuer is in top form at the wrong moment.
"He took the goalkeeping game to a new level - unfortunately for us."
Neuer proved crucial during the goalless first half, with a fine double stop to deny Neymar before grasping a glorious opportunity that Kylian Mbappe struck too close to the 34 year-old.
After Coman opened the scoring, Neuer produced another excellent save with his right boot to preserve the advantage that ultimately led Bayern to a repeat of its 2012-2013 treble.