Duke (16-3) and Virginia (18-3) will meet afterward in the other semifinal. When the Blue Devils and Cavaliers faced off at Virginia midway through the regular season, Duke recorded a 19-18 triumph in double overtime.
The final will be at 7 p.m. Sunday.
"It was definitely a horrible loss," Cavaliers coach Julie Myers said. "But it was one of those things that had to happen for us to get where we are today."
Coming off a 10-6 finish in '06, Penn earned a berth in the postseason by winning its first Ivy League title since 1982.
The Quakers registered tournament victories over Boston University and Maryland to reach the brink of the national championship game. Penn is 8-0 at home this spring and owns a school-record 13-game winning streak.
"The team did a fantastic job all year, with each game just being that next rung on the ladder to get us closer to getting home-field advantage" in the tournament, said Penn coach Karin Brower, who, in her eighth season, guided the Quakers to their first NCAA tournament since 1984. "It makes it that much more special. And it makes it a lot more fun."
Becca Edwards, a graduate of Springfield (Montco) High School whose goal in Penn's 9-7 quarterfinal win over Maryland snapped a 5-5 tie and gave the Quakers the lead for good, is looking forward to playing in such a big game with family and friends in attendance.
"Being from this area, it's nice that my high school team can come and people who support you will be able to see you in the big arena," said Edwards, a sophomore who joined teammates Allison Ambrozy and Melissa Lehman in scoring two goals each against Maryland.
"We worked so hard all year and last summer," Edwards said. "Everybody really put everything they have into this. Seeing our hard work pay off is really going to be exciting for everybody."
The first time Edwards and her teammates played Northwestern, it was the fourth game of the season for both teams, and the Quakers suffered a 13-4 loss.
The hosts jumped out to a 5-1 advantage, but Penn trailed by only 6-4 early in the second half. However, Northwestern scored the last seven goals.
"They caused turnovers and ran away," Brower said. "Northwestern is a great team on offense, and their defense makes you play a different type of offense than you'd like to play. But our defense has been solid for us all year. It gives our attack an opportunity to win games."
Northwestern hasn't gone down since a season-opening loss at North Carolina that wasn't settled until two overtimes had been played.
Northwestern coach Kelly Amonte Hiller has kept an eye on Penn. The Wildcats advanced by downing Holy Cross and Syracuse.
"As a team, Penn has jelled," Hiller said before citing the Quakers' come-from-behind victories over Syracuse and Maryland as evidence of the threat they pose. "They've shown they can overcome deficits, and that's a credit to the job Karin has done with them."
NCAA Division I Women's Lacrosse Final Four
Tonight at Franklin Field.
No. 4 Penn (16-1) vs. No. 1 Northwestern (19-1),
Coaches: Penn, Karin Brower, eighth season. Northwestern, Kelly Amonte Hiller, sixth season.
Outlook: Northwestern, which boasts an aggressive defense, is the only team to defeat Penn this season. The Wildcats are the two-time defending champions. Penn is looking for its first NCAA championship.
Key players: Penn defender Hillary Renna is usually assigned to opponents' top attackers. Renna has caused 11 turnovers this season. For Northwestern, attacker Kristen Kjellman leads the nation's top offensive team with 62 goals and 23 assists.
No. 3 Virginia (16-3) vs. No. 2 Duke (14-3),
45 minutes after the first semifinal.
Coaches: Virginia, Julie Myers, 11th season. Duke, Kerstin Kimel, 11th season.
Outlook: Duke ranks second nationally with 15.42 goals a game, well ahead of its school-record pace of a year ago. Virginia ranks ninth nationally in scoring margin, having outscored its opponents by 107 goals, or 274-167. In the meeting between the teams earlier this season, Duke won, 19-18, in sudden-death double overtime.
Key players: Duke attacker Caroline Cryer led the Atlantic Coast Conference with 67 goals. She also has five game-winning goals. In the tournament, Virginia's Kate Breslin already has 11 goals. The midfielder has 65 goals and 23 assists this season.
- Shannon Ryan
Contact staff writer Kevin Tatum at (215) 854-2583 or email@example.com.