After having clinched the Atlantic 10 regular season championship Friday, Sunday’s win for the Massachusetts women’s lacrosse team was the icing on the cake.

And for seniors Rachel Vallarelli, Morgan Walker and Amy Tiernan – who were honored on Senior Day – the cake tasted even sweeter after Sunday’s 18-11 win over George Washington at McGuirk Stadium.

Tiernan finished with a career-high seven points on four goals and three assists while Vallarelli played all 60 minutes in the cage, recording six saves.

The Minutewomen (16-1, 1-0 A-10) found themselves in unfamiliar territory as the Colonials (6-10, 4-4 A-10) scored the first two goals of the game, both coming from Gabbi Hull, who finished with three goals and an assist.

UMass, however, answered with nine of the game’s next 10 goals, including a stretch of eight unanswered to give the Minutewomen a commanding 9-3 lead with 12 minutes, 38 seconds remaining in the half. UMass took a 12-5 advantage into the break.

Erika Eipp also tied Tiernan with a game-high seven points, matching her total from Friday’s victory over Richmond. Eipp scored a trio of goals in addition to four assists. Hannah Murphy, Katie Ott, Nicole Troost and Abby Walker also contributed with a pair of goals each.

Both the Colonials and Minutewomen battled back and forth in the second half as each side recorded six goals apiece in the final 30 minutes. GW scored the final four goals of the game, including two in the final minute at the 11-second mark and two-second mark.

Rachel Mia – the A-10’s top goal scorer – and Michaela Lynch each scored three goals for the Colonials while goalie Mackenzie Jones recorded nine saves.

UMass, the now six-time defending conference champion, will play George Mason in the conference semifinals Friday at 1 p.m. The Minutewomen beat the Patriots 17-7 earlier this season.

Andrew Cyr can be reached at [email protected] and followed on Twitter @Andrew_Cyr.