"It is what it is," Eastern coach Jamie McGroarty said. "We know them. They know us. We've been the best two teams in South Jersey this whole season."
The teams, which have split time as either the No. 1 or No. 2 team in The Inquirer Top 10 all season, have evenly divided three games: one win each and one tie. They played four times last season and three times in 2011.
Eastern (21-1-2), the No. 2 seed, took care of business against third-seeded Williamstown on a chilly, windy afternoon on the Vikings' turf field.
Eastern dominated the first half, taking a 2-0 lead on a penalty kick in the 12th minute by Konstantinides and a goal by freshman Amirah Ali on a rebound just 74 seconds before intermission.
"They pressured us," Williamstown coach Dan Torcasio said. "In the second half, I thought we held our heads high. But they took it to us at the beginning of the game."
Williamstown (19-3-1) got strong play from goalie Taylor Bynoe, who made 14 saves, including a pair of diving stops.
Eastern got a big lift from the return of Ali, who had missed the first two games of the tournament with an ankle injury.
"It was great to come back and score a goal," Ali said.
Eastern's victory sent the Vikings into the sectional final against Lenape for the third year in a row. Thursday's game will be the 11th meeting between the rivals since 2011, but the last for the seniors on both sides.
"Sophomore year they beat us and last year they beat us," Konstantinides said. "We know each other so well. It's like the rivalry has always been there.
"It would be really nice to get one back from them, especially senior year."
See and hear from Eastern senior Miranda Konstantinides.
Williamstown 0 0 - 0
Eastern 2 0 - 2
Goals: E-Miranda Konstantinides, Amirah Ali.
Saves: W-Taylor Bynoe, 14; E-Imani Taylor, 8.