With No. 12 Centreville threatening to creep ahead Thursday night with less than two minutes to play in a Virginia AAA Northern Region girls’ basketball semifinal, Edison Coach Dianne Lewis considered pulling freshman guard Jada Graves.

“She had this look on her face like, ‘Oh God, what’s going on?’ ” Lewis said. “I looked at the bench and [then] things just kind of happened the way they happened.”

What happened was within a span of 17 seconds, Graves scored on a drive to the hoop and then off a steal to stretch the lead to seven points to help lift No. 14 Edison to a 58-53 win over the Wildcats at Robinson.

In the second semifinal, South Lakes held off defending region and state champion Oakton, 48-46, to reach the region championship for the first time since 1986, when Seahawks Coach Christy Winters Scott was a senior at the school.

The championship is Saturday at 6 p.m. at Robinson. Both South Lakes and Edison also secured state tournament berths.

Edison (23-4) is in the final for the first time since winning back-to-back championships in 2006 and 2007. Three of the top four scorers are freshmen.

“I knew [we] were a talented team,” Lewis said. “Not quite convinced they were a championship-caliber team yet. I know they have all the tools to get there. But I kind of thought maybe the inexperience might come back to bite us. But the kids are hungry. They want to learn. They want to win.”

Graves led Edison with 20 points and the team’s lone senior, forward Sheila Sherrill, added eight points and 10 rebounds.

Centreville (24-3) trailed by 11 early in the third quarter but rallied to tie the game with 6 minutes 13 seconds left on a three-pointer by sophomore guard Caroline Wakefield.

The Eagles ran the lead back to seven but were up by three when Graves scored on those two drives. She also hit all four of her free throw attempts in the final seconds.

“I was getting kind of frustrated, but it was a mentality thing, and I got my head back in the game,” Graves said.

Junior guard Jenna Green led Centreville with 12 points.

In the second game, South Lakes (23-4) scored the first nine points of the fourth quarter to break a 32-all tie. Oakton (22-5) pulled to within three with 17 seconds left when sophomore guard Lindsey Abed hit two foul shots.

Abed (season-high 17 points) later scored on a drive with about five seconds left to make it a one-point game, and South Lakes junior Colette Toma hit a foul shot with 3.2 seconds left for the final margin.

The Cougars were playing without senior center Elizabeth Manner, who broke her thumb in the first-round game Monday. She averages 24 points.

South Lakes senior guard Gabrielle Schultz scored 13 points. Junior center Abigail Rendle added 11 points and nine rebounds.

Winters Scott played on South Lakes teams that won region titles in 1985 and 1986.

“When you’re a coach, you know the joy that the players feel, having been a player and feeling that,” she said. “I guess it’s double as a coach.

“Ten games ago, maybe I would have been concerned about [the late-game pressure]. But this is the fourth game in a row where we’ve had a one-possession game. So I think mentally that might have helped us prepare for this moment.”