It didn't take long for the second annual Washington Post Holiday Classic to produce a major surprise.

No. 17 Good Counsel, which has been trying to improve its program in recent years to be competitive with the upper echelon of the Metro Conference, converted 25 of 30 free throws in the second half and withstood a furious late surge by No. 8 Coolidge yesterday for a 68-56 opening-round boys victory at Georgetown University's McDonough Arena.

The Falcons (9-0) will meet No. 14 Potomac (Md.) tonight in an 8:45 semifinal. The Braves (4-1), overcoming a sluggish start, played tenacious second-half defense to defeat Bethesda-Chevy Chase (4-2), 50-44. University of Texas-bound guard Robert Garner led Potomac with 20 points.

In other first-round games, 6-foot-9 senior center Bart Lammerson scored 20 points and had 19 rebounds as Madison (5-0) defeated defending tournament champion Springbrook, 71-64. Daryl Franklin scored 18 points for Chantilly (5-0) in a 75-48 win over Flint Hill (4-4).

Madison meets Chantilly in a 7 p.m. semifinal tonight.

In the inaugural girls Post Holiday Classic, No. 6 Fairfax and No. 14 Lake Braddock took advantage of cold-shooting Montgomery County teams Whitman and Blair to create an all-Northern Virginia final.

Mara Cunningham had 20 points and 11 rebounds as Fairfax held the Vikings to one field goal in the first half in cruising to a 46-26 triumph in the first semifinal. Lake Braddock blitzed Blair, 14-0, over a seven-minute span of the second half and went on to win its semifinal game, 54-38.

Fairfax (5-0) plays Lake Braddock (5-0) for the championship today at 5:15. Blair (5-1) meets Whitman (4-1) in the consolation at noon.

Good Counsel was elated with its victory over perennial Interhigh power Coolidge (6-3).

"Everybody was saying, 'Well, Good Counsel is undefeated, but they haven't beaten anybody,' " said Good Counsel Coach Joe McCall. "We needed a good breakthrough win to beat a good team and this was it. It was really the biggest victory that I've ever had as a coach and it's good for the kids going into the league season."

The Falcons only converted two field goals in the final 8:20, but both were momentum-builders. After a steal, Kurt Small (16 points, seven rebounds) scored off a dunk with 20 seconds left in the third , pushing the Falcons' lead to 49-36.

Then, after sinking eight of 11 free throws five minutes into the final quarter, Nii Nelson-Richards (game-high 25 points, five rebounds) broke loose for a dunk following a long inbounds pass that kept the Falcons in control, 59-49, with 2:11 left.

In the girls semifinal, the 6-foot-3 All-Met Cunningham used her five-inch height advantage for five inside baskets as Fairfax jumped out to a 12-0 lead en route to a 31-7 halftime advantage.