Shannon Boxx scored on a penalty kick in the third minute of second-half injury time to lift the Sol to a 2-1 win over the Boston Breakers on Sunday in a Women's Professional Soccer game in Cambridge, Mass.
Boxx's penalty kick came after Boston defender Alex Scott was called for a foul -- and subsequently received a red card -- on forward Marta in the penalty area.
The Sol, which finished the regular season with a league-best record of 12-3-5, has clinched a spot in the inaugural championship game at the Home Depot Center on Aug. 22 against an opponent to be determined.
Boston (7-9-4) took a 1-0 lead in the 17th minute when Kelly Smith took a pass from Kristine Lilly and fired a shot past goalkeeper Karina LeBlanc.
The Sol tied the score in the 60th minute when Marta scored after taking a pass from midfielder Aly Wagner. It was Marta's league-leading 10th goal.