David Patterson, who recently won his second straight Gorin junior tournament, won two matches yesterday and gained this morning's semifinals of the 12th annual Bobby Bowers Memorial at Springfield Golf and Country Club.

Patterson, the Maryland state high school champion from Dulaney High near Baltimore, easily defeated Robert Andrews of Fairfax, 6 and 5, in a third-round match, then was 2 under par in dispatching Jeff Greenberg of Midlothian, Va., 3 and 2, in the quarterfinals.

In this morning's ages 16-17 semifinals, Patterson will play co-medalist Chris Haarlow of Pinehurst, N.C., while Alan Myers of Severna Park faces Frank Edwards of Martinsville, Va.

Patterson, who lives in Lutherville, said he was not putting well even in winning two matches Tuesday. He changed the gauze covering the grip of his putter for yesterday's play and sank four birdies against Greenberg. He had a four-foot par putt on the 16th green to end the match. "I was tired," he related. "I said, 'Let's make this putt and get it over with.' "

Tara Hipp, the Maryland state high school girls champion from Gaithersburg High, eliminated Amy Hooks of Bethesda, 2 and 1, in a girls quarterfinal.

Hipp, who plays out of Montgomery Village, will oppose Amy Green of Springfield this morning at 8. The other semifinal matches Kim Cayce, daughter of Congressional head pro Kent Cayce, against defending champion Karen Jefferson of Seaford, Del.

Said Hipp, 15: "To win here would really make my summer."