Over the years, Valery Gergiev seems to have illuminated most of the landmarks of the Russian orchestral repertoire to British audiences. But there are still plenty of Slavic highways and byways unexplored even by this indefatigable musician. And in this Prom with the London Symphony Orchestra, who were on notably excellent form, he uncovered several more.

Borodin's second symphony, with which Gergiev started, was once an orchestral staple. Its relative neglect in recent decades is simultaneously explicable and perverse, as the symphony is compact, distinctive and historically influential. But not even Gergiev's energy and Borodin's orchestral palette could disguise the piece's tendency to stolidness.

Alexander Glazunov's second piano concerto, dating from 1917 but betraying not the slightest trace of a society in convulsion, was the highlight for anoraks. The brightly articulate playing of the much-touted Daniil Trifonov did everything it could to raise the interest level of this suavely written yet musically complacent score, but Trifonov's showy encore, Guido Agosti's transcription of the Danse Infernale from Stravinsky's Firebird, had more energy in one bar than Glazunov could muster in his entire concerto.

So to the evening's two unqualified highlights. Sofia Gubaidulina's The Rider on the White Horse, distilled from her 2002 oratorio St John Easter, was stunning in conception and realisation, with Gergiev marshalling immense forces, including a viscerally powerful Albert Hall organ, in a performance of awesome clarity and colour. And the account of Mussorgsky's Pictures at an Exhibition, in the Ravel orchestration, was Gergiev at his best. Occasionally, this seemingly permanently overworked conductor appears to be winging it. But not this time. Here, he delved into every bar, persuading the LSO's trumpets, horns and tubas to conjure a truly fruity Russian brass sound, and drawing a tinglingly elongated alto saxophone solo from Simon Haram. With Gergiev living every episode and audibly urging his players forward throughout, this was a memorable performance of huge theatricality and vividness.

* On iPlayer until Tuesday. The Proms continue until 7 September. Details: bbc.co.uk/proms

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