A year ago, Blackstenius scored the only goal in the final when Arsenal beat Barcelona. There could be a repeat at Ullevål in Oslo on May 23.
Arsenal can largely thank Lyon goalkeeper Christiane Endler and the French team's Norwegian defender, Ingrid Engen, for that.
After just under an hour, Engen was the last on the ball as Endler allowed an easy rebound from a free kick that made it 1–1.
In the 83rd minute, the Lyon duo collided while trying to clear a failed back pass. It ended with Arsenal's Olivia Smith getting an open goal, and the final score was 2–1.
Blackstenius played 84 minutes for Arsenal.
The return leg in Lyon will be played on Saturday.
