The Quad City Symphony had to contend with a last-minute change in soloists - and the piece he was playing - for the opening Masterworks concert of its 100th season. But the orchestra on October 4 dug deep to unearth world-class playing to match legendary pianist André Watts - and in the process seemed to exhaust itself. With a popular symphony and the world premiere of a commissioned piece in addition to a piano concerto with Watts, the intensity and high artistic level of playing were exhilarating to hear, but the orchestra didn't sustain them in the second half of the program.