Poignancy and optimism: Herbert Blomstedt and the Philharmonia in cathartic Brahms and Beethoven

It definitely feels like summer. The sun is brighter, the grass is greener, the temperature is warmer and the short sleeves are out. But at a time when people would normally have a spring in their step and generally feel positive, this week's tragic events have resulted in a subtle change of mood: the step has become a defiant stride, and positivity has turned into compassion. In all its many guises, the power of music in catharsis can be quite extraordinary, and it is exactly this frame of mind that makes you want a concert like this – music that is forceful, poignant but with an overriding sense of optimism.

The evergreen Herbert Blomstedt, now in his 90th year and showing no signs of abating more than 60 years after his conducting debut, delved into his core repertoire and led the Philharmonia Orchestra in a programme of music laced with emotion and energy. Blomstedt introduced the concert by saying that the collected performers dedicated this concert to the victims of the tragedy in Manchester, adding that the music of Brahms and Beethoven tonight had "a very special meaning".

Martin Helmchen gave a powerful and sombre performance of Brahms' Piano Concerto no. 1 in D minor which, remarkably, was the composer's first orchestral piece to be performed publicly. Following the full drama of the opening passages, Helmchen's unassuming but absorbing style was soon paying dividends. His first entry was subtle, melding into the fading orchestral chatter and then weaving a web over the keys as he continued the dialogue. Everything in this performance seemed to have just that little bit more – more bite, more poise, more contemplation, just more. This was down to Blomstedt's and Helmchen's healthy partnership, two artists at opposite ends of their careers who really thought this one through.

Helmchen managed the most delicate of feathery touches and cultured an air of deep reflection, particularly in the Adagio where the orchestra's wonderfully melting sound revealed a veneer sheen from the strings and some sympathetic wind ensemble work. But there was force and aggression too, with bucketfuls of zest and vigour in the outer movements and no shortage of technical mastery, which Helmchen simply eased through and turned into flowing conversations. Blomstedt guided the orchestra sensitively, with swathes of emotion ebbing and flowing, and not allowing the robust scoring to overpower the soloist. There were just one or two moments where it felt a little too static and listless, with a couple of minor timing issues in the Rondo, but this was an honest, forthright performance, emotionally charged and full of confidence, intimacy and intense power.

Beethoven's Symphony no. 7 in A major had Blomstedt and the Philharmonia making sure that this became a full-on exuberant expression of the human spirit. Energetic and relentless from beginning to end, Blomstedt's hands chopped and sliced sharply through the air to get every last ounce of energy out of the players, who left nothing behind. He gave particularly careful attention to the Beethovenian extremes in dynamics, and his subtle phrasing gave shape and cohesion to the whole work. The Philharmonia simply sparkled. There were some sublime wind solos, especially from flute and oboe, but then again the whole woodwind section sounded deliciously lustrous and bright. The strings were at their gritty and emollient best, and the brass sound was full and fruity. The Allegretto, encored at its première, had a ruminant quality, and the massive bursts of energy in the furiously paced Finale were incessant. The overall effect was magnificent, though at the minor expense of losing some of the detail from the pulsing inner voices, as is often the way, but the liberating feeling of being carried along with the fervent driving force, rocking and rolling like a runaway train, was irresistible, with the result that adrenalin was pumping long after the final bars.