The 20-year-old forward intercepted a return in front of the guests' goal barely five minutes into the first period and tricked in the puck with a backhand.
It meant 2-0 for Brynäs.
- I barely saw.
I just saw the puck down at my feet and tried to wave it in, nice that it slid in, Birgersson told C More in the first period break.
Oskarshamn reduced to 1-2 in the second period, but in vain.
Brynäs eventually won 3-1 and took their second straight victory in the SHL.
The Gävle team thus lifted from twelfth to tenth place in a limping table.
Oskarshamn is eleven.