Among the many free concert events offered to the Washington community, the series known as Mozart at the World Bank deserves high marks, judging from yesterday afternoon's performance by the Manchester String Quartet. It kicked off a week of hour-long programs, all taking place at the World Bank Auditorium on G Street NW, between 19th and 20th streets. The auditorium is plush, comfortable and sonically excellent. It holds only 300 seats and these concerts, now in their third season, have been known to attract twice that many spectators.

Yesterday's program was attended by a business-suited crowd, many of whom squatted on the floor when the seats were gone. They listened raptly as the Manchester Quartet delivered some ravishing Mozart and Dvorak.

This is the first season in which Mozart is not the only composer on these programs. As with other all-Mozart ventures, sooner or later the Mostly Mozart syndrome takes over. One can hardly complain when the playing in Dvorak's "American" is of yesterday's caliber. The Manchesters are four young string players from the National Symphony Orchestra. Where they found the time, not to say the knowledge, to play quartet music like this is cause for wonder. A cliche' has it that beneath every orchestra player is a frustrated soloist. In this case the secret yearning was obviously to play chamber music at the very highest level. And the Manchester Quartet has no cause to feel frustrated.

The violist, Lynne Edelson Levine, never got lost in the violin's lower notes or the cello's middle ones. She was a distinct entity, although never at the expense of ensemble. The first violinist, Hyun-Woo Kim, played with breathtaking tenderness and reticence.

Their Mozart offering was K. 575, the first of the three so-called Prussian Quartets. These last of Mozart's quartets are often compared unfavorably with the six dedicated to Haydn. The Manchesters went a long way toward demonstrating that K. 575, at least, belongs on the same high level. The cello never dominated, although Glenn Garlick made the most of his many solos.

The four remaining concerts in the World Bank series promise further delights: piano trios by Mozart and Beethoven today, clarinet sonatas (Mozart and Brahms) tomorrow, a fascinating mix of vocal music on Thursday, and back to all-Mozart on Friday (quartets for flute or oboe and strings). Try to catch one of them, at least. But get there early.