Concert-goers at Orchestra Hall in Chicago were all stunned Thursday because of two men who were fist fighting in one of the boxes during a Brahms preformance.

Maestro Riccardo Muti was nearly through the second movement of Brahms Symphony No. 2 at the normally staid Chicago Symphony Orchestra when the two patrons went at it.

The Chicago Sun-Times reported Saturday that the fight began when a man in his 30’s started punching a 67-year-old man in one of the boxes

“’We heard a rather loud thump,” said Steve Robinson, general manager of Chicago’s classical and folk music station 98.7 WFMT, who was at the performance but didn’t see the fracas.

“It wasn’t so loud that everyone jumped up and ran for the exits.”

Concert-goers at Orchestra Hall in Chicago were all stunned Thursday because of two men who were fist fighting in one of the boxes during a Brahms preformance

Police said the fight was the result of an argument over seats. The older man had a cut on his forehead; the other left before officers arrived.

All the while, the concert went on. Though patrons said Music Director Riccardo Muti gave the two men a sharp, irritated look – one person called it “dagger eyes” – before continuing on with the third movement.

“Mind you, he never stopped conducting,” Steve Robinson said.

“He very gracefully, without missing a beat – literally – he brought (the second movement) to a very quiet and subdued close, while still looking over his left shoulder.”