When it comes to Prokofiev binges in London, Valery Gergiev's got form. While his recent Proms marathon of all five piano concertos was variable, I hold fond memories of his symphony cycle with the LSO in 2004, a staggering achievement which was the foundation for his eventual appointment as chief conductor. Gergiev is the most committed advocate for Prokofiev, so it is no surprise that in this 125th anniversary year, he is leading the celebrations. Not content with all seven symphonies, he programmed the three string concertos too, over just three nights. Too much in this all-you-can-eat Prokofiev buffet?

With two opera houses plus a concert hall to service, the Mariinsky Orchestra must call on a huge pool of players. This particular configuration seemed younger than usual: of the 47 string players employed (22 female), barely half a dozen can have been over the age of 50. The appetite with which they tucked into three mighty scores was astonishing, a couple of cracks in the brass façade during the Seventh Symphony betraying only the slightest hint of fatigue. The strings make an athletic, muscular sound, the sometimes raw brass section supplies reminders of the rough Soviet sound from crackly Melodiya recordings. Players take a cavalier approach to tuning (the assiduous harpist excepted), with slipshod intonation from the horns and the odd splash of vinegary oboe. You can't argue that it doesn't have character. Under the trademark tools of Gergiev's armoury – toothpick baton, grunts, quivering hands – the Mariinsky was harried into urgent, sometimes prickly performances.

The Sixth Symphony was ushered in to open the evening, Gergiev riding the juggernaut of sound amply filling Cadogan Hall, though – from the Gallery, at least – not overwhelming the venue. A scything trumpet cut through the Largo's great theme, the strings revelling in the high-wire soaring violin melodies. Prokofiev's ballets are never far away. Woodblocks recalled Cinderella's midnight chimes and mighty, romantic climaxes seemed to leap straight from Romeo and Juliet. Ghostly celesta and harp tolled and double basses slithered unceremoniously. There was an unvarnished quality to the playing, often visceral, the Vivace finale imbued with buccaneering spirit.

The Sixth and Seventh symphonies alone, with perhaps a brief curtain-raiser, would constitute an ample programme. The addition of the 40-minute Sinfonia concertante, Prokofiev's revision of his earlier Cello Concerto, risked bloating it, were it not for Alexander Ramm's fine performance. Earning second prize in the 2015 International Tchaikovsky Competition, this tall, youthful cellist, with a mop of unruly hair à la Steven Isserlis (but without the curls) is a real talent. His sound is big-boned, with soulful legatos, iron pizzicatos and percussive attack which made easy work of Prokofiev's wiry writing in an admirably taut account. The Mariinsky's accompaniment was sketchy at times, the first horn having the good grace to look embarrassed after a mangled solo. Ramm's terrific Gaspar Cassado encore, infused with earthy Spanish inflections, was well-received.

Runners, I am told, get addicted to marathons. Gergiev must be infected with the same addiction. While some of the audience bailed out at this point, he just kept going. I briefly hit “the wall” in the opening movement of the Seventh Symphony, but recovered thanks to the breathless second movement Allegretto, rallied by the ripe, rasping trombone and luscious string phrasing – the best orchestral playing of the night. The Mariinsky's stamina saw them home in style for a very late finish (22:20 by my watch). Quite how they could conjure the light-hearted Vivace's level of insouciance, with its helter-skelter percussion and glockenspiel glitter, is anyone's guess.

Significantly, this was the only concert in the series which hasn't ended with an encore. Even Gergiev knows he can only test an audience's patience so far.