“The sound of church bells dominated all the cities of Russia I used to know,” said Sergei Rachmaninov. “They accompanied every Russian from childhood to grave, and no composer could escape their influence.” By extension, we may also include the sound of Russian Orthodox chant to those influences. Rachmaninov was not an especially religious man, yet he composed religious music, most famously the haunting All-Night Vigil (or Vespers). Liturgical chant and a whiff of incense also found their way – perhaps subconsciously – into his symphonic works, fascinatingly explored across Sunday's two Proms.

It was Russian-American musicologist Joseph Yasser who first identified the remarkable similarity between the opening of Rachmaninov's Third Piano Concerto and the ancient Znamenny chant “Thy tomb, O Saviour, soldiers are guarding”. Rachmaninov claimed he did not quote from any source, but “sang” his melody at the piano as a singer would sing it. Preceding Alexander Gavrylyuk's probing account of the concerto with the BBC Scottish Symphony Orchestra, the Latvian Radio Choir performed this chant, starting from the back of the hall, processing through the prommers and thronging the Arena before descending below the Albert Hall stage. Conductor Thomas Dausgaard segued straight into the concerto and the chant's resemblance to the piano's opening phrase was striking. Russian Orthodox chant is full of intervals of a fourth and the fourth plays a significant role in Rachmaninov's vocabulary too – not for nothing has he been dubbed the “poet of the subdominant”. Rachmaninov's phrases are also characteristically long-breathed, with notes moving in steps of small intervals, giving them a vocal quality.

The choral prelude also helped to draw out spiritual aspects of the concerto. The piano's opening phrases were entwined by a creeping bassoon line that crooned like a cantor. Gavrylyuk offered a delicate, reverent account, low on flash and glitter and the barnstorming decibels often heard in this repertoire staple. He often played on the sonorous tintinnabulations of Rachmaninov's chords, while faster passages rippled with clarity. Dausgaard, barely taking his eyes from his soloist, ensured the BBCSSO were the most attentive partners, strings aching wistfully, yet he could raise the temperature when required, especially in the feverish canter to the finish line and the punchy sign-off which stamps out Rachmaninov's name.

If the link between the chant Serene Light and Rachmaninov's Second Symphony was less marked – the Latvian Radio Choir performing from the Gallery after the interval – there was, nevertheless, something liturgical about the way the woodwinds' chords were inflected after the sepulchral opening sigh from the cellos and double basses. This was a much more excitable performance than the concerto. Dausgaard immediately drew an ardent string sound, the first movement bristling with restless energy. Trombones glowered, a lone cor anglais pined. Central to the performance was the Adagio, Yann Ghiro gorgeously phrasing the famous clarinet solo in a long arc, the strings echoing its romantic sweep. If the Adagio yearned and sobbed, the finale danced, driven along exuberantly.

After emerging briefly for air, we were back in the hall for the Late Night Prom, the Latvian Radio Choir performing the Vespers. Conductor Sigvards Kļava pulled the tempi about in the opening invocation to worship, but thereafter this was a spacious, beautifully profound reading. With just 24 singers, there was an intimacy to their performance despite the vastness of the venue. 

Composed by Rachmaninov in less than two weeks during 1915, the All-Night Vigil makes huge demands on singers' breath control and intonation, yet the Latvians coped admirably with clean textures though little of the plangent tone or attack one associates with Russian choirs. Basses just about plumbed the B flat depths at the end of “Blessed is the man” while tenors displayed sweet tone high up in their register and voiced the tolling bells in the Nunc dimittis well. In the centrepiece “Blessed art Thou, O Lord”, sopranos and altos floated their Alleluias nicely, phrases which Rachmaninov later incorporated into his swansong, the Symphonic Dances. Kļava, unhurried, shaped each movement sympathetically before an attentive audience. An ethereal end to an often spellbinding evening.