For a programme of familiar favourites, this afternoon's performance featured a few surprises. Clearly Mirga Gražinytė-Tyla has found her feet with the City of Birmingham Symphony Orchestra and isn't afraid to be a bit experimental. The packed Symphony Hall audience lapped it up and responded warmly to the sheer force of energy emanating from the stage.

Conducting without a baton, Gražinytė-Tyla was mesmerising in her use of expressive, balletic arms, seemingly increasing her diminutive height with broad sweeping movements but equally employing fingertips to conjure up the finest of details. Even from behind, you could somehow tell she was smiling, and the orchestra was obviously having fun. Opening with Haydn's Symphony no. 31 in D major “Hornsignal” got proceedings off to a flying start with the horn fanfares. Written when Haydn was employed at Esterházy, it's a product of an increased inventiveness borne of being so isolated from Vienna, hence four horns rather than the usual two. An exciting introduction, with the contrast of a beautiful flute melody, led into a poised Adagio, with fine solos by violin and cello. The balance between instruments to the fore and accompanying strings, whether bowed or pizzicato, was always spot on, the conductor controlling the dynamics and atmosphere with great skill. Tempo variations too, such as the energetic changing up a gear into the Menuet, kept the audience hooked through to the final reprise of the hornsignal. Very listenable and very well received.

Of course, it was expected that there would be some scene-shifting before Mozart's Piano Concerto no. 27 in B flat major, but nobody was expecting Francesco Piemontesi to be sitting with his back to the auditorium, the piano square-on almost within striking distance of those in the middle of the front row. Gražinytė-Tyla jumped onto her centre-stage podium so that she faced the pianist and, fascinatingly, the audience. This music-in-the-round arrangement gave us what is usually an orchestra-eye-view of the conductor's antics, and confirmed that, yes indeed, she smiled but also made effective use of expressive eyebrows! It could have been tricky for the woodwind section as they were faced with her back but she indulged in a good bit of swivelling and in any case the CBSO woodwind never appear anything less than wonderful!

The one sensory drawback was seeing only the pianist's back but his playing was totally captivating. After a warm and committed orchestral introduction, Piemontesi launched into the delightful delicacy of Mozart's final piano concerto, progressing onto a commanding cadenza, gorgeous tones filling the hall. The poised Larghetto offered a veritable dialogue between piano and orchestra, with Gražinytė-Tyla keeping the ensemble together with minimal direction and clearly loving the music. The flamboyant Allegro saw Piemontesi scampering up and down the keys as tension was relieved. His expressive tempo changes were the embodiment of a rich mixture of the entertaining and the sublime. By the time he finally faced the audience, beaming, we were clamouring for more – which we (including Gražinytė-Tyla, perched behind the double basses) received in the shape of the slow variation from Mozart's "Dürnitz" Sonata (3rd movement) K.284, a real delight.

After the interval came the second surprise, and you could sense people wondering whether there'd been a change to the programme. Instead of the first four iconic notes of Beethoven's Symphony no. 5 in C minor, ominous timpani and brass struck up what turned out to be the march from Purcell's Music for the Funeral of Queen Mary. This apparently unprogrammed couple of minutes certainly heightened the sense of anticipation so that when the Beethoven finally exploded in the hush there was real dramatic impact. The attack and impetus was phenomenal, almost giving a sense of something alive that might get out of control, but Gražinytė-Tyla had matters very much in hand. In amongst the sustained energy and brilliant teamwork of the riveting full orchestral sound, there were nuggets of hushed pizzicato playing, martial music followed by the warmth of legato expressiveness and the chance for individual instruments to shine as the theme was passed around. Toe-tapping textural intensity had the audience rapt.

Gražinytė-Tyla stood among the orchestra as she took the prolonged applause, and was eventually moved to share a few words of thanks. As well as a brilliant musician, she's clearly a people person. Commenting that it was the birthday of one of the string players, she mused that not only was the orchestra itself a miracle but that it was made up of 100 individual miracles – everybody counts.