The girls from Montgomery County started out as a filler team -- the final group added to complete a field of four in a local basketball tournament for 12-year-olds. Three months later, they returned from Port Allen, La., as the natonal champions in the Amateur Athletic Union's Junior Olympics.

The young team, Potomac Valley, became the Washington Metropolitan champions even though its members had never played together before May. And earlier this month it went on to win four games in three days to capture the first national tournament ever held for girls their age.

Unseeded Potomac Valley registered victories over the three top seeds in the 14-team tournament, including a 28-26 win over second-seeded Kansas City in the finals. The Kansas City team is a four-time Missouri state champion in its age group.

The team's regional victory, over the Fairfax Police Youth Club, was an upset.

The Montgomery County team was hastily put together by combining two teams from a Montgomery County Recreation Department league. Steve Carberry, coach of the Brookmont team, and Coach Jerry Gardner of Garrett Park were invited to enter a team in the regional tournament only to complete a field that already had three Virginia teams.

The Montgomery County team was not supposed to win. "The whole thing was put together so the Fairfax team would win the tournament and go to the national tournament in Louisiana," said Carberry. "But we surprised them -- we went out and won the tournament."

Winning both the regional and national tournaments probably was not as hard as what came in between -- raising enough money for the team to travel to the Baton Rouge suburb (about $6,000). The girls spent much of their time at bake sales, yard sales and selling raffle tickets instead of practicing layups.

In July, Gardner and Carberry entered the seventh graders in a Montgomery County summer high school league for practice. The girls went 2-2, and were not embarrassed in losing to the Bethesda-Chevy Chase varsity, 35-18.

"Our main goal was to pick up the pace of their play," said Carberry. "Playing against girls their age, they played well for that level. Playing against high school girls, they picked up their pace immediately, kept it for three weeks, and never lost it."

Gardner said his only ambition going into the tournament was for his girls to play "class basketball." He never imagined they would go to the top of the class.

The team picked up two members from the Fairfax team it beat in the regional championship, as allowed by national tournament rules. With the addition of Paula Schuler and Christy Winters from the Fairfax team, Gardner and Carberry set out to prepare for the tournament, not knowing the quality of basketball they would be facing. They designed their team around defense, concentrating on person-to-person defense instead of the zone defenses played at most levels of girls basketball.

"Jerry told me before the tournament, 'We may find a faster team, we may find a bigger team, but I can't imagine finding a bigger, faster team,' " said Carberry. "Then after the first day of games, he told me he found that team."

The team Gardner saw was from Tennessee. The coach was Mary Lou Johns, who is the head coach of the Memphis State University women's team. She had put together of team of 12-year-olds with a trio of starting forwards all over 6 feet tall. Potomac Valley defeated Tennessee, 36-33, in the tournament's second round.

The team averaged an amazing 48 percent shooting from the floor over the first three games of the tournament, and shot 50 percent against Tennessee. More remarkable was that Potomac Valley lost the ball through turnovers just five times -- about one-fourth the normal amount -- against the team Gardner thought was the best in the tournament.

In the finals, Kansas City led most of the way. Potomac Valley tied the game, 24-24, with two minutes to go. A steal by Karin Vadelund led to a basket by Brett Gardner, who is Coach Gardner's daughter. With 1:10 remaining, Michaela Carroll hit an 18-foot shot for a four-point lead.

The game was not decided, however, until JoJo Rein, Potomac Valley's 6-foot-1 center, blocked a game-tying layup attempt in the final 20 seconds. Rein also topped the winners with 10 points and nine rebounds. Rein, Carroll and Gardner were selected to the all-tournament first team. Ann Carberry, Coach Carberry's daughter, was named as an all-tournament honorable mention.

Other team members were Marissa Caputo, Evie Greenawalt, Christy Winters, Paula Schuler, Tamara Lowe and Tracey Meringoff.

National champions at age 12 can be a hard act to follow. Carberry and Gardner plan to reassemble their original teams for recreation league play next winter, where they will be foes again. But they also will try to keep their championship team together.

Carberry would like the championship squad to play against high school girls, but Gardner has a more imaginative idea: He would like to see the girls play against boys their age.