Last night at the Kennedy Center Concert Hall, conductor/pianist Daniel Barenboim opened what might be called his fall season here -- in a powerful, superbly poised account of the Beethoven "Emperor" Concerto with conductor Charles Dutoit and the National Symphony Orchestra.

Barenboim follows this "Emperor" with the Washington Opera's new production of Mozart's "The Marriage of Figaro," which he will conduct tonight. Then he returns to the orchestra Tuesday for another "Emperor" and next Thursday he will switch to the Brahms D minor concerto for his second week with the NSO.

A bit of a stunt, you may think? Not even remotely. There isn't another person today who is more unequivocally serious about his music making than the protean Barenboim. In this time of pianist/conductors, violinist/conductors and so on, one of the dual pursuits almost invariably suffers for the sake of the other. Barenboim is the masterful exception.

His authority in Beethoven's music is so assured that the digital brilliance Barenboim showed in the final movement seemed almost secondary to the subtlety of his rhythms and the extraordinary clarity and breadth of his phrasing. Throughout the concerto there was striking cohesion within each movement, with sections rising naturally out of what came before. The result was unflagging momentum without even the slightest sense of rush in the process.

Barenboim continues to be a pianistic wonder, just as he was in his stunning recital here last fall. It is unclear how a man who spends most of his time conducting can continue to maintain his piano playing at such a level.

The orchestra and Dutoit took much the same large view of Beethoven's musical architecture, and interaction of soloist and orchestra was skillfully meshed.

The other work on the program was Prokofiev's exalted and monolithic Fifth Symphony. Like similar symphonies by Shostakovich, the Fifth is unrelenting in its intensity, but it is not as unremittingly grim as Shostakovich can be.

The National Symphony's performance was strong, but not as polished as it might become. And there was some questionable ensemble, especially at a point near the end of the second movement where Dutoit apparently cued the brass a bar or two early for a reprise of the trio.