Chantilly junior guard Alena Koshansky usually conducts herself in a business-like manner, nonchalantly accepting high fives from her teammates after making big plays.

But after she converted a timely steal into a layup and gave the Chargers a comfortable 74-55 lead over Mount Vernon with 3 minutes, 9 seconds remaining, she pumped her right fist triumphantly in the air, knowing she buried the Majors and secured her team's first-ever trip to the Group AAA State Tournament.

``I was excited to be up by that much," said Koshansky after the Chargers defeated Mount Vernon, 78-58, in a Northern Region Tournament semifinal Thursday night at the Patriot Center. Chantilly meets West Springfield at 7 p.m. Saturday in the region tournament final. ``[I was thinking] we got it."

With about two seconds remaining, Chantilly senior guard Kimi Argy stood near the top of the key, smiled and threw the ball toward the Patriot Center roof. Then the rest of her teammates formed a mob around her.

``This is just an awesome feeling," Koshansky said.

Koshansky tallied a team-high 21 points and 12 rebounds, and sophomore guard Kate Argy (20 points) helped secure the historic victory by hitting three 3-pointers in the fourth quarter.

Mount Vernon (23-3) cut a 12-point Chantilly lead down to four with an 8-0, third-quarter run. The Majors got a boost off the bench from Clarice Kent, who scored the last four points during the spurt and got her team within 44-40 with 3:20 left in the third quarter.

But the Chargers scored the third quarter's last six points, as a Kate Argy fastbreak layup with 5 seconds left gave the Chargers a 50-40 lead.

When Mount Vernon double-teamed Koshansky, Chantilly made the Majors pay by swimming the ball and finding open shooters on the perimeter.

With Chantilly leading, 58-46, with 6 minutes remaining, Kate Argy hit back-to-back to three-pointers, increasing the lead to 64-46 with 4:52 left. ``Having the larger court [at the Patriot Center] helped us some," Chantilly coach John Kelly said.

Mount Vernon, thanks to hot shooting from Lauren Troupe, led, 15-12, at the end of the first quarter. The senior center hit two long jumpers and grabbed five rebounds in the period. She finished with a team-high 19 points.

But the Chargers alternated between 2-3 and 3-2 zones throughout most of the game. The zone defenses worked, as the Majors shot 3-for-16 from the field in the second quarter.

``We tried to mix it up to confuse them a little bit," Koshansky said.

Chantilly started the period on an 8-2 run - five of those points came in transition - capped by two Caitlyn Gorski free throws.

Then the Chargers, already in one-and-one situations with 2 minutes, 52 seconds left, cashed in at the free-throw line. In the final 1:38 of the first half, Chantilly went 6-of-6 from the stripe. Kate Argy gave her team a 32-24 lead heading into the locker room, hitting two free throws with 25.1 seconds remaining in the first half.

Mount Vernon coach Kenny Farmer said the Majors missed a few easy shots in the first quarter, allowing Chantilly to stay within striking distance in the second period.

``If you leave good teams hanging around," Farmer said, ``they're going to make you pay."

W. Springfield 54, Madison 51

As West Springfield's players prepared to board a bus headed back to their school after the Spartans' dramatic 54-51, come-from-behind victory over Madison, freshman guard Laura Haskins approached Spartan coach Bill Gibson and asked if she could ride home with her parents so she could get some extra rest.

Gibson granted her permission, jokingly telling her she could because she hit two big free throws with 19.1 seconds remaining that accounted for the final score of Thursday's Northern Region Tournament semifinal. More importantly, Haskins' hustle seconds before her free throws epitomized West Springfield's inspired play in the fourth quarter, when the Spartans erased an eight-point Madison lead.

After Janielle Dodds hit a spinning lay-up with 38 seconds left, giving the Spartans a 52-51 lead - their first in the second half - the 6-foot-3 senior center tipped a pass intended for LaToya Walker, prompting a mad scramble for the ball. Haskins dove for the ball and called time out, denying the Warhawks (21-5) an opportunity to take the lead.

Dodds, who scored eight of her team-high 24 points in the fourth quarter, said the team hadn't played at a high level in the first three quarters.

``We told ourselves, `We need to play now,'" Dodds said. ``We started to play when we realized we wanted it."

Madison coach Denise Wojciech said the Spartans (24-3) used a 1-2-2 zone press that forced a few key turnovers in the fourth quarter. That, in turn, allowed West Springfield to run the floor.

``We deserved that game, and everybody in the building knew that,'" Wojciech said. ``We just made some mistakes down the stretch."

The teams were tied at 12 after one quarter before Madison got a spark off the bench from Kim Blessing. With the Warhawks trailing, 21-18, Blessing (14 points) hit back-to-back three-pointers from almost the same spot on the left wing. And when LaToya Walker hit a shot in the lane with 3 seconds left in the first half, Madison entered halftime up, 30-25.

Then Tara Eddy scored eight third-quarter points, six of them coming during an 8-2 run that gave the Warhawks a 44-33 lead with 1:30 left in the third. The senior scored 14 points in her last high school game.