The first opera in Wagner's Ring Cycle is the second to be taken from the Mariinsky's concert performances in St Petersburg – Die Walküre is out already. True to form, Valery Gergiev tackles Wagner with the same excitement he brings to all his music-making. With that intensity comes a waywardness, usually concerning tempi. In the prelude the Rhine seems ready to burst its banks far too soon. When the giants Fasolt and Fafner arrive they do so almost in slow motion. But then the pace settles. Most of the cast, led by René Pape as Wotan, are strong though some of the diction is indistinct. The orchestra is superb. All told this is a characterful and compelling account. Siegfried and Götterdämmerung follow next year.