Mozart’s great half-dozen string quartets dedicated to Haydn were spread over two concerts by the Barcelona-based Cuarteto Casals. If the second was occasionally infuriating, it was genuinely refreshing, too.

From the ringing opening of K458 through to the hurtling close of the Dissonance quartet, K465, there was the sense that the players had polished the pivotal moments until they shone, but had kept passages in between free to be interpreted by each individual. It was mainly first violinist Abel Tomàs who threw out the surprises, one moment shaping melodies with impeccable poise, the next seemingly experimenting – a soupy slide here, an extreme contrast of vibrato and non-vibrato there. In the central section of the encore, the scherzo from Haydn’s Op 33 No 2, Tomàs made a woozy slide a feature of each and every bar.

The other three musicians also brought distinctive voices to the mix: Vera Martínez-Mehner’s muscular second violin, Jonathan Brown’s warm, at times impatient viola. The cello playing of Arnau Tomàs, the violinist’s brother, was often beautifully understated yet distinctively metallic when hammering out the drum-like rhythm in the third movement of K464.

Tempos were so fluid that the underlying motor did not always feel rock solid, yet somehow the music kept a powerful sense of direction. These might not be Desert Island Discs performances, but in the hall the quartet’s fullness of sound plus the exhilaration of not knowing quite what would happen next made for a winning combination.

• Broadcast on Radio 3 and iPlayer on 17 January.