Joining the great Gewandhausorchester, soprano Rachel Willis-Sørensen gives us a Richard Strauss program that’s mightily impressive. This is late Strauss, so the colors are golden, mellow, and autumnal, and the superb Leipzig ensemble is completely inside that unique soundworld. Willis-Sørensen’s voice has a dusky quality, especially in the lower registers, which allows her to blend with, and then soar out of, the orchestra, as in “Frühling.” “Beim Schlafengehen” is beautifully crafted, her voice soaring, as if being set free. The Capriccio closing scene—in which the Countess Madeleine grapples with the very essence of opera (word or music?)—shows Willis-Sørensen alive to every little nuance of the text. Nelsons is a fine partner and clearly an accomplished Straussian.