The newly-promoted side who finished first in the regular season made a strong start on Friday, winning 4-1 at Monitor ERP Arena, and were keen to make home advantage count again before the series heads to Skelleftea for games three and four.
A fourth successive win in total looked in the bag after the first period, as Brynas took a 3-0 lead.
Linus Olund's scrappy shot in the 10th minute was somehow not clawed away by the Skelleftea defence, before Greg Scott deflected a second past the goaltender just a minute later.
Great work from Tyler Vesel and Michal Svrcek then set up Olund for his second and the home side's third goal in a dominant two minutes and nine seconds of play.
Jakob Silfverberg had the chance to make it 4-0 in the first period, but his penalty was saved by Gustaf Lindvall.
But Skelleftea, who finished fifth in the regular season, hit back in the second period.
A good finish from Oscar Lindberg on a powerplay shortly after the midway point was reward for their dominance, before Anton Heikkinen found the top corner four minutes later when the away side again had a man advantage, to make it a one-goal game.
That hard work was almost undone late in the period, but Brynas again failed with a penalty shot, this time Victor Soderstrom could not find the target.
Despite that miss, the momentum swung back in the home side's favour in the third period, but it took until its 18th minute for them to finally seal the win.
Olund was sent through on goal, and where his teammates had failed one-on-one against the goaltenders, he held his nerve to beat Lindvall and complete his hattrick.
A second for Heikkinen completed the scoring in the final minute, but the 4-3 win on the night and the 2-0 series lead belong to the team from Gavle.
Game three in Skelleftea takes place on Tuesday evening.
