Pianist Tzimon Barto returned to the NSO under the baton of mentor Christoph Eschenbach. (Courtesy of Kennedy Center)

Christoph Eschenbach is fiercely loyal to a cadre of musicians he has discovered, mentored and partnered with over the years. It’s customary to roll one’s eyes a bit when discussing such blind loyalty, particularly when some of the musicians don’t hit the mark, at least as conventional wisdom sees it.

It’s especially customary to roll one’s eyes when discussing it in reference to pianist Tzimon Barto. In the classical music world, Barto is known as a flamboyant bodybuilder given to extreme mannerisms while playing and to extravagant gestures while not, such as when he recites his poetry onstage before his encore.

But Thursday night with the National Symphony Orchestra, the only extreme thing onstage with Barto was Bartok’s second piano concerto, a fiendishly difficult piece that Barto, looking positively restrained in a standard-
issue tux, played as if it were no problem at all.

As for the encore, it was the same piece Barto offered in Philadelphia, minus the poem — just a quiet, taut performance of the middle movement of the Bach’s keyboard concerto in F minor, BWV 1056.

Barto isn’t a perfect performer, but he’s often an interesting one. Now 50, he deserves a second hearing from those who have dismissed him for his flowing pirate shirts and excessive emoting. With the Bartok, certainly, he neither pounded nor grew self-consciously quiet; rather, he maintained an easy, flowing tone as the mean from which he expanded into brilliant fireworks in the final movement or retreated into a tiptoed hush in the second.

I find something exhilarating in Bartok to begin with, a sense of place and rightness and possibility. This concerto premiered in 1933, and it’s anchored in a mid-20th-century sensibility, with early Stravinsky behind it (lots of “Petrushka” echoes) and Leonard Bernstein lying in the future, waiting for its exuberant syncopations to catch him.

It makes sense that Barto and Eschenbach have had such a long and warm collaboration. Eschenbach also is an artist who pushes the envelope in unconventional ways and often takes heat for it. And Eschenbach can be as mannered as any active musician today.

Take, for example, the exaggerated pause after he slammed on the brakes in Beethoven’s “Egmont” overture, which opened the program. The overture sounded labored at the outset, as if its dark, tense chords were a little more work than they needed to be — until a meltingly graceful string line rose from the murk. Eschenbach is wonderful at making sweet passages touch the ear with the soft warmth of springtime air.

With this program, the orchestra also is warming up for its upcoming European tour; Barto will join the NSO in Paris to reprise the concerto in February. Another tour change was just announced: The withdrawal of the violinist Julia Fischer, another of Eschenbach’s pets, means that Arabella Steinbacher will be the soloist in Mozart’s fifth violin concerto.

The fact that the orchestra has to warm up for the tour made for slightly odd programming this week. The only thing that the “Egmont” overture, the Bartok concerto and the Brahms Second Symphony appear to have in common is that their composers’ names, in a time-honored classical tradition, all begin with B.

The Brahms seemed like overkill after the intricacies of the Bartok, all the more as the orchestra lacked crispness and definition. There were some strident brass passages in the Bartok and a muddiness that kept the final movement from shining as it could have. And this muddiness carried over into the first movement of the Brahms, where the second theme sounded chaotic, even hysterical. Still, Eschenbach whipped the orchestra to a rousing close, lifting Thursday’s audience to its feet for the second time that evening.

The first time was for Barto, and it was deserved. Underwhelmed as I am by some of Eschenbach’s pets, the conductor’s tenure in Washington has also given me a chance to give some of them a second hearing and — in some cases — to not only applaud his loyalty but also to gain a new appreciation of his taste.