Västerås started the match best and took a 2-0 lead after goals from both Edit Ljung and Charlotte Selbekk.
AIK equalized soon after through Diana Lipanova, who stood until the break.
But in the second half, Västerås punctuated the match when former goalscorer Ljung first scored another goal, and Tova Grönoset later scored to make the final score 4-2 to the away team.
Karina Lipanova reduced, but AIK did not get closer than 2–4.
"Nice feeling"
Västerås can thus decide the series in their next meeting.
- We have a good feeling with us from the quarter-finals.
We've been working more as a team lately.
Such a nice feeling in the team, says Tova Grönoset to Elitserien Live after the final whistle.
In the second semi-final, the big favorite Villa Lidköping won away to Skirö 5-2 after they unexpectedly took the lead in the 16th minute.
The teams meet again on Saturday, March 11.