Rachmaninoff's 'Dies Irae' haunts BSO's all-Russian program

South Korean pianist Seong-Jin Cho delivered an electrifying performance of Rachmaninoff's "Rhapsody on a Theme of Paganini" with the Boston Symphony Orchestra, part of an all-Rachmaninoff program that also featured the Symphony No. 2. Cho's interpretation, colored by his affinity for French music, was uniquely mesmerizing, with the "Dies Irae" motif haunting the piece. He offered a Chopin waltz as an encore, while the orchestra added an extra Wednesday concert to meet ticket demand. Conductor Andris Nelsons led the hourlong Symphony No. 2 without cuts, but the orchestra's execution was uneven, ranging from sublime to lugubrious. The finale's soaring energy felt like an afterthought, with Nelsons's detail-focused approach sometimes hindering unified momentum.