The Swedish national team striker scored the last goal of the match three minutes into the second half.
Blackstenius cut deep, rounded home goalkeeper Kirstie Levell before easily rolling in 4–0, the 26-year-old's fourth league goal of the season.
Blackstenius was replaced with ten minutes left to play, while Lina Hurtig was replaced 20 minutes into the second act.
For Hurtig, the match came to an abrupt end when she was replaced ten minutes later with an injury.
It is currently unclear what this is about.
It was 4-0 to Arsenal, who with the victory moved up to the league leader.
The London club have won all six games so far and are three points ahead of Manchester United.
For Blackstenius and Hurtig, a break from the national team now awaits, the duo is part of the Swedish national team that will face Australia on November 12 away in a training international match.