Freshman Troy Webster sank a 19-foot jump shot from the top of the key with one second to play last night to complete a 30-point game and give George Washington a 68-66 victory over Massachusetts at Smith Center.

A crowd of 1,650 noisily celebrated the Colonials' second victory in seven Atlantic 10 Conference games. Coach Gerry Gimelstob was noisy afterward, too, but he was not offering his players congratulations.

Gimelstob launched a tirade, replete with four-letter words, that could be clearly heard far down the corridor outside the Colonials' dressing room. The gist of his expurgated message was that the Colonials, Webster obviously excepted, had been horrible.

They certainly were horrible over the last 9 1/2 minutes, as they failed to get a field goal until Webster's winner. With 12 1/2 minutes left, GW was ahead, 58-39, and most observers were more concerned with the weather than the outcome.

Suddenly, however, Massachusetts, pretty awful itself for most of the night, began to go inside with success. The Minutemen took control of the offensive boards and, when they weren't scoring, were drawing fouls and making the free throws.

Eight straight points made it 62-56 and, in the process, GW center Mike Brown picked up a charging foul, his fourth. Then Brown, pushed by Bobby Braun, retaliated with a shove and the resulting double foul sent Brown to the bench.

Gimelstob disputed that call with all three officials and the game was delayed five minutes while the debate continued.

When play resumed, the Colonials were disoriented and threw up some wild shots, while unable to pull down a rebound. Massachusetts took advantage and was able to close to 66-64 when Darryl Carter followed up two missed shots with 2:27 left.

At this stage, Gimelstob had Mike O'Reilly, a 29 percent foul shooter, and Dan Sullivan, a 33 percenter at the line, in the game. Massachusetts chose to foul O'Reilly, who missed for the 20th time in 27 foul shots this season. When Massachusetts' John Hempel was fouled by Craig Helms, he made both and with 48 seconds left the 19-point lead was gone.

Gimelstob yanked Sullivan, but O'Reilly still was in there, a tempting target for another foul. Instead, Massachusetts inexplicably permitted the Colonials to hold the ball for a last shot and Webster sank it to deal Massachusetts (5-14) its third two-point loss in the last four games.

Webster had hit from about a foot farther out with two seconds remaining in the first half for the game's only three-point shot and a 41-26 lead. In fact, Webster scored GW's last seven points of the first half and first eight points of the second half before 6-5 Horace Neysmith took over the job of guarding him with a measure of success.

Webster, an all-America high school player at Clifford Scott High in East Orange, N.J., became the first Colonial to score 30 points since Wilbert Skipper got 34 against George Mason two years ago.

Brown had 10 of GW's 23 rebounds, as the Minutemen, with no notable height advantage, grabbed 31. Except for the poor board work, the Colonials played fairly well, committing only five turnovers.