There’s no better way for a conductor to mark a birthday than with a concert. At least that seemed to be one of the ideas behind Benjamin Zander’s appearance Friday night at Symphony Hall. A day after turning 84, the UK-born maestro led the Boston Philharmonic Youth Orchestra, which he founded eleven years ago, in performances of music by Bartók and Tchaikovsky.

For sheer energy and intensity, the night’s readings belied any suggestion Zander has aged out of Simon Rattle designation of him as “the world’s oldest teenager.” In terms of polish and musical understanding, too, the night’s offerings forced one to yet again put out of mind the fact that the BPYO is an orchestra made up of teenagers.

Managing the last was especially impressive considering that the program’s first half consisted of Béla Bartók’s Concerto for Orchestra. This 1944 score is rightly famous and beloved. It is also fiendishly difficult: in writing for the most technically accomplished orchestra of his day (Serge Koussevitzky’s Boston Symphony Orchestra) Bartók pulled no punches.

Yet, on Friday the Concerto’s challenges held no terrors for the BPYO. Rather, its swirling string figurations, exposed woodwind lines, and spitting brass fugues all spoke with tonal clarity, rhythmic security, and a firm sense of character.

Throughout, Zander’s reading was rooted in the score’s debts to folk music and the composer’s personal struggles while writing the piece, exiled by war from his native Hungary. The results were notable for their warmth and lyricism.

This was evident from the first movement’s introduction, in which the low-string and woodwind writing—highlighted by principal flute Grace Helmke—sang beguilingly. Equally impassioned were the “Elegia’s” climactic outbursts, here lined in velvet, and the nobly fervent, viola-led theme of the “Intermezzo.”

Not everything was sober and strict, though: the latter also boasted delirious mocking figures (not to mention spot-on trombone glissandos) in its central Shostakovich satire. And the second movement’s duets were delightfully droll.

Ultimately, Friday’s account of the Concerto outlined an affecting journey from darkness to light, and Bartók’s contrapuntal writing always drove robustly. The subtle spots glowed, such as the phrasings in “Giuoco delle coppie’s” chorale and the burbling winds at the start of the “Elegia.” By the time the finale’s Technicolor coda, with the BPYO brasses resplendently in the lead, rolled around, the sense of triumph felt decisively and honestly won.

A similar arc of expressive development marks Tchaikovsky’s Symphony No. 5. Friday’s interpretation of the Fifth was rougher than the Bartók—low strings and brasses were periodically out of balance with the rest of the ensemble and there were a couple of spotty moments from the horn section—yet the overall performance burned hot.

That was invigoratingly true of the crowning moments in the first two movements, which offered a bracing combination of edge-of-the-seat tension and soulful lyricism. In the first, the fast music danced, by turns gingerly and furiously. Meanwhile, principal horn Graham Lovely’s second-movement solos wanted nothing for warmth, tone, or expressive urgency.

Though Zander took the “Valse” at a gracefully slower clip than usual (which resulted in some unsettled mid-movement string passagework), the finale snapped. Phrasings were flexible–the second subject exhibited an ear-catching touch of repose–while the dovetailing of brass lines at its heart was flawless and the peroration blazed.

Was the performance sometimes insistent and impetuous? Did it occasionally wear its heart on its sleeve? Of course: this was Tchaikovsky lived wholly, and often thrillingly, in the moment. As such, Friday’s proved about as fresh, captivating, and celebratory a Fifth as they come.

Click here to listen to Bartok’s Concerto for Orchestra.

Click here to listen to Tchaikovsky’s Symphony no. 5.