Buffon failed to stop David Alaba's long-range effort after just 23 seconds and then conceded another goal to Thomas Muller, as the Bianconeri lost the first leg of their Champions League quarter-final tie 2-0.
"How was he positioned? He seemed like a pensioner," he told reporters. "Alaba shot from 120 metres away.
"I don't want to upset him, but he should have kept that shot out. Perhaps Gigi didn't think that Alaba would shoot from so far.
"Bayern were focused from the first until the last minute and Juventus hardly had a shot on goal. The result is tight for us, we should have won by three or four goals."
The second leg of the tie will be played in Turin next week.