It’s midmorning, less than 12 hours after he finished another grueling performance as the tormented Amfortas in Wagner’s “Parsifal,” and Peter Mattei is already singing again.

“My voice is in perfect shape. I could do a show tonight,” the Swedish baritone said last week. “I check after each performance. I sing some Bach, some lieder, because I want to make sure everything’s OK. So far, so good.”

Better than good, the critics agree. James Jorden in the New York Post praised his “velvety baritone,” while Manuela Hoelterhoff for Bloomberg News enthused: “I don’t think better singers exist anywhere in the world, especially Peter Mattei as Amfortas.”

Listeners have a chance to judge for themselves March 2, when a live matinee performance will be broadcast on the radio and shown in HD on movie theaters worldwide. Headlining the cast of the new Francois Girard production are tenor Jonas Kaufmann in the title role, bass Rene Pape and soprano Katarina Dalayman. Daniele Gatti conducts.

Amfortas, though a supporting role, is crucial to “Parsifal.” He’s the leader of the Knights of the Grail, but he is unable to perform his duties because of a wound. His two long monologues in acts one and three are punctuated by cries of rage and remorse, often over heavy orchestration.

When Mattei agreed to debut the role at the Met, he was known mostly as a Mozart singer, and the only Wagner he had sung was the lyrical Wolfram in “Tannhaeuser.” At first, Mattei confided, “I was a little nervous to do it. Wolfram for me was spot on, but I knew Amfortas was a step up dramatically. But I try to do it in the same way as Wolfram, because the beautiful melodies are really there.”

Mattei said he wasn’t familiar with “Parsifal” when he began studying the role last summer.

“I found it a very good piece to not know so much about,” he said. “Then you can just listen to the music.”