At 32 the Lithuanian conductor Mirga Grazinyte-Tyla is already music director of the City of Birmingham Symphony Orchestra, a post held by Simon Rattle before we called him "Sir". She was handed a musical obstacle course to show her stuff in Los Angeles, however, when she conducted the Philharmonic in a series of weekend concerts featuring Patricia Kopatchinskaja. After keeping the orchestra together seamlessly with the impulsive Moldovan in Tchaikovsky's Violin Concerto, and shouldering the responsibility of an Unsuk Chin world premiere, Gražinytė-Tyla simply let Debussy's darned elusive La Mer play itself.

The night belonged to Kopatchinskaja who wowed the young, high energy crowd first when she came on stage with her ruby red slippers, and again when she slipped them off before Gražinytė-Tyla dropped her baton. From her first entrance it was clear that Kopatchinskaja was going to carve out the narrative with exaggerated, often cosmic, sometimes compelling, sometimes coy and mewing, sometimes almost inaudible sotto voce, sometimes double dotted, sometimes near the bridge sul ponticello. She used sparingly but effectively a variety of little scoops and portamenti. Some of her upward swoops in the first movement cadenza sounded like the donkeys braying in Carnival of the Animals. All of this was on top of numerous ongoing adjustments to Tchaikovsky's basic structure, pace, and rhythm, plus supernaturally fast triplets in the first movement which even she couldn't keep up with, and then an insanely fast speed for the Finale which had everyone gasping for breath.

This was Tchaikovsky raw and fierce as if he had written it – as he might have – for a young lover. It was not a matter of playing everything with pure, seductive, burnished tones, impeccably in tune no matter what the degree of difficulty, like a Heifetz or a Bell; it was a matter of life and death. The crowd wanted to give her a standing ovation after the first movement but she and Gražinytė-Tyla gracefully acknowledged and moved on in a way that made the audience feel good not disciplined. The Canzonetta was also personally phrased and, as throughout, sold with body language, Kopatchinskaja moving freely about through 360 degrees, even stomping and dancing when she needed to; it was very much like chamber music and definitely a love affair.

After the furious Finale made its daring escape, Kopatchinskaja donned black gloves and played for her encore György Kurtag's mad parody Hommage à Tchaikovsky on an upright piano, and gave it a thoroughly melodramatic performance. The audience loved the joke but were disappointed when it became clear that despite their continued entreaties Kopatchinskaja was not going to play an encore on her violin.

In the world premiere of Unsuk Chin's SPIRA, A Concerto for Orchestra, Gražinytė-Tyla commanded sprawling blocks of sound, vivid textures, and sonorities, often under the pressure of extreme dynamic settings, and all almost completely unhindered by melodies, which may be explained by the fact that Chin derived the title from the "spiral curve, nicknamed Spira mirabilis by the 17th-century mathematician Jacob Bernoulli and was influenced by the "biological process of growth and metamorphosis, with complex material evolving from simple germ motives in unexpected ways".

Although a very large orchestra filled the stage almost to overflowing, the key instruments were two vibraphones, each with a player and regulator, which opened and closed Chin's 20-minute process in sound. There were moments which felt like getting lost outside the Emerald City, of vast bird song, of Biblical Hollywood, and it finally ending as it had begun in glacial movement. The Philharmonic made all sorts of wonderful noises. For her part, Gražinytė-Tyla found everything in the music but fantasy.

In her anti-climactic reading of La Mer, the colors seemed less fresh and shimmering than they usually do – perhaps it was in comparison to a brilliant new score written 100 years later which benefited directly from the composer's decade-long working relationship with the orchestra to exploit Disney Hall to its fullest audiophile glory.

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