Last week, Barcelona beat Atletico Madrid 7-0 in the Spanish Super Cup final.
Rolfö was involved from the start and also had to score goals.
And efficiency continued against Real Betis.
With barely an hour left and at the position 3-0, Rolfö was replaced - and she only needed four minutes to find the net.
The 28-year-old kept a careful lead on an input from Lieke Martens and could easily put in 4-0.
Before that, teammate Asisat Oshoala had completed a hat trick.
The full hit is Rolfö's seventh goal of the season.
Barcelona now has 18 straight wins in the league game and places itself in first place.