When the German pianist and conductor Bruno Walter first heard Gustav Mahler’s Symphony No. 1 in D Major, he “marveled at the singular courage” of the composer. Walter went on to become Mahler’s assistant, and the symphony, sometimes called the “Titan,” eventually took its place as one of the olympian works of the late Romantic period in classical music.

With Maestro Xiao-Lu Li directing, the Bangor Symphony Orchestra gave the First a titanic workout at a concert Sunday at the Maine Center for the Arts in Orono. Before the hour-long extravaganza, Li told the audience that the Mahler was an inspirational work for him but one that required patience.

So which is it: courage or patience?

I vote for a third requirement: surrender. The Mahler work is so large, so complex and yet so rapturous that it deserves complete imaginative devotion from the listener – right up to those crashing final 10 minutes. The rest is up to the orchestra. The BSO coaxed out the drama, plowed for brightness and bloomed with that Mahlerian garden of plunges, surges, eruptions, folk dances, marches, tattoos, and boyish mischief – even as there were patches that were less refined than the overall success of the performance.

In the end, the BSO was rewarded with unbounded enthusiasm, and rightly so, especially for the numerous soloists and juggling sections that kept to Li’s ambitious plan for the work.

The concert opened with a driving portrayal of the overture to Verdi’s “La Forza del Destino,” and also paired with soloist Alexander Fiterstein for Carl Maria von Weber’s Clarinet Concerto No. 1 in F minor. Li and Fiterstein, who plays with declarative surety and grace, performed this piece together last year in Ohio, and they zipped along like old friends with the BSO breathily keeping up. If any limpness crept into this performance, it wasn’t Fiterstein’s fault. In an encore, he further charmed the audience with a crisp rendition of the cadenza from Aaron Copland’s Clarinet Concerto.

Typically, the strings lead the BSO fun but Sunday was a banner day for the brass, percussion and woodwind sections, which Li generously singled out for appreciation at the end of the concert.