Two 18-year-old University of Maryland golfers, Eric Smith and Mark Lawrence, gained the quarterfinals of the Virginia State Amateur championship at Washington Golf and Country Club yesterday.

They were joined by Neff McClary of Fairfax, former District amateur champion; Marty Alford of Norfolk, former Naval Academy golf captain; Bill Sibbick, University of North Carolina senor; Timmy Baker, University of South Carolina; Marvin Smith, a recent graduate of the University of recent graduate of the University of Richmond, and John Long of Manassas.

All of the afternoon matches were close, four of them being decided on the 18th hole. No match was won by a bigger margin than 3 and 2.

In today's morning matches, Long faces Eric Smith; McClary meets Alford; Baker will be matched against Lawrence and Sibbick goes against Marvin Smith. Play begins at 9 a.m.

Lawrence disposed of Gerald Hanweck, of Reston, in his afternoon match, 2 and 1. He had a 6-up margin at one point but Hanweck battled back and was two down and one to go when the 17th was halved to end it.

Eric Smith is the younger of two Maryland golfing brothers (the other is Steve) who play out of Forrest Park Country Club in Martinsville, Va. Eric had to get past John Price, current Washington Golf and Country Club champion, 3 and 1, in the afternoon. Steve, 20, was eliminated by Alford.

Eric was 2 up on his afternoon opponent, Bobby Inman, after 15 holes. Inman won the next two holes. Eric put his ball in the trees on the 18th, was out in two, and was up and down from the fairway making a 10-footer for a par four. Inman three-putted for a bogey.

Long had a tough match in the afternoon against 50-year-old Nelson Broach, the 1963 winner of this tournament. Long was 2 up after 10 holes but lost the 12th and 15th when the match went level. Long went ahead at 1 up again with a birdie on the 16th and halved the next two holes. Long, who went to the semifinals of the Belle Haven four-ball with Dave Allen, is playing in his first Virginia state tournament.