Mussorgsky's Boris Godunov consists of a series of scenes from the tsar's history, several of them starring different characters, so there's plenty of opportunity for one of these to steal the show. In last night's performance at Savonlinna, there were a number of attempted robberies.

The first of these came from Giorgi Kirof as the bibulous monk Varlaam. Egged on by Vuokko Kekäläinen's Innkeeper (every bit as entertainingly sozzled), Kirof gave us a rumbustious account of Ivan the Terrible's siege of Kazan, Russian dance moves included, and was brilliantly convincing in the scene in which he exposes Grigory's deceit.

Another attempt at daylight robbery came from the diminutive Dan Karlström as the Holy Fool whose last kopek is stolen by the street urchins but who refuses to bless Boris for giving him alms. It's one of the most compelling scenes that Mussorgsky (or, arguably, anyone else) ever wrote, and Karlström's high, clear and plaintive voice was spellbinding.

Throughout the evening, the Savonlinna chorus, grown by an additional 20 members over that of last night's Tosca, made a vigorous effort to make the show their own. Mussorgsky gives the chorus some exceptionally fine tools with which to do so, starting with the opening scene in which the policeman coerces an erratic populace into chanting in support of Boris. The scene has a particularly Russian hilarity, and feels alarmingly timeless – this could be Putin's Russia as easily as Ivan's. In the huge plainchant infused scenes of the coronation and St Basil's Cathedral Square, the chorus was simply magnificent, drowning us in a tidal wave of sound.

But for all these determined efforts at larceny, the show remained the property of its rightful owners: Matti Salminen as Boris and conductor Leif Segerstam. Salminen has been one of the great basses of his era, and those in the audience who saw him in his heyday a decade or two ago will have mourned the passing of the sheer vocal heft of the man. The deep bass growl may have gone, but Salminen's artistry remains undimmed: the phrasing, the depth of meaning inflected into every word, his physical presence and his simple but effective gestures. Two scenes stand out: his tyrant's bluster and violence collapsing into self-doubt in the face of Shuisky's guile, and the pathos of the death scene as Boris disintegrates in the arms of his son.

Taras Shtonda's Pimen gave us a long and happy immersion in the depths of Russian basso profondo, although his scene is a long one and my attention flagged slightly in the middle. Other vocal roles were generally well sung, notably Anna Immonen as Xenia, but there were a few voices overpowered by the orchestra: Christian Juslin as Shuisky and countertenor Artem Grutko as the tsarevich Feodor both suffered.

The central concept of Nicola Raab's production is thoroughly sound: a golden cage from which Boris cannot escape while the crowd throngs outside. It's well executed by designer George Souglides, acting is generally well directed, and Raab makes excellent use of St Olaf's Castle's various nooks and crannies to deliver telling off-stage chorus numbers. But the production was marred by errors of detail. To give two examples of several: the illusion of the golden cage was damaged by moments when the crowd entered it, while Grigory's escape looked very odd as he passed through a part of the stage hastily vacated by policemen only moments earlier. Linus Fellbom's lighting belonged to the “mostly dark with occasional splashes of colour” category: it's a style which I normally dislike and I disliked it here. I get the idea – bright lights for the nobility, darkness for the downtrodden masses – it's just that I prefer seeing what's happening on stage to being required to peer through darkness at it.

The orchestra excelled. The insistent four note pattern that infuses Boris Godunov came through superbly, the oriental gongs and bells added colour, and the music's power and unmistakably Russian were palpable. Segerstam is not a well man, and had to be assisted onto the stage for his curtain call. As he and Salminen embraced in a huge bear hug, the rapturous response of the audience confirmed what I had already been told: this production is almost certainly the Finnish opera public's last chance to see this pair of their greatest artists together, and it's a moment of great emotion and significance for them. Apart from being an excellent evening's opera which touched the heart of Boris Godunov, this was a Finnish swan song as potent as anything penned by Sibelius.