When the fingers of Marian McPartland fly over the keyboard in jam showdowns with jazz greats Chick Corea, Oscar Peterson and Alice Coltrane, there's no time for second thoughts.

McPartland, who is the host of the 4-year-old "Piano Jazz" show broadcast over National Public Radio, returns to Charlie's in Georgetown Tuesday through Saturday.

She arrived in the United States from England 37 years ago, and turned a six-week gig at the Hickory House in New York into a 10-year stay there. "I guess I've been here long enough to absorb some of the jazz firsthand. After all these years here, coming over here, being a part of the jazz scene here, I still feel very humble about it. Having that NPR show is a real inspiration."

The repertoires of the guest pianists who play with McPartland range from the classical to the avant-garde. She teasingly remarked that musicians, especially George Shearing, "like to trick you" when they play duets.

"Jazz in England is not that different--we're all great jazz fans," she said. But that "we're all" is still small change in the music world. "Jazz is a kind of minority music no matter where you are. It's something very special. You just don't hear it on every radio station--the rock stations tend to block it out," McPartland said, hastening to add that "I'm not antirock, just 'anti' some rock."

Spreading jazz to the popular audience is one mission McPartland has equipped herself for well; in the early 1970s she cut her own album, and has since released 18 albums under her label, Halcyon. With the help of Gary Mazzaroppi on bass, she plans to entertain the audiences at Charlie's with a medley of Harold Arlen songs and some of her own material.

But there'll be no duels. Unless, of course, Stan Getz wanders in, she said.