But Arsenal locked down in defence โ except for early in the second half โ and created the best chances. Only two superb saves by Barcelona goalkeeper Cata Coll to deny Frida Maanum and Blackstenius kept it scoreless until Blackstenius finally beat her.
The victory marks an incredible finish to a rocky season for Arsenal, which included coach Jonas Eidevall resigning and being replaced by assistant Renรฉe Slegers.
Since taking over, Slegers steered the team through a spectacular European campaign. Arsenal built its confidence from come-from-behind wins over Real Madrid and eight-time champion Lyon in the knockout rounds before laying low the almighty Barcelona.
The loss was a huge disappointment for the large group of Barcelona fans who filled the stadium that is home to Sporting Lisbon. Blue-and-burgundy shirts and flags outnumbered the red-and-white section, but their calls of โYes we can!โ in the final minutes werenโt enough to inspire a comeback by the Catalan club.
โWe are very sorry for all our fans who have come to support us,โ Bonmatรญ told Catalunya Radio in the field before the award ceremony. โWe will try to do it again.โ
Arsenal shook off some early jitters in defence and soon had Barcelona on the back foot. Its pressure up the field stopped Barcelona from getting its possession game going, and Arsenal found spaces with long balls down the left flank.
England striker Russo was a rock for Arsenal, using her size to win balls and keep the attack going.
Arsenal thought it went ahead in the 22nd but a video review waived off an own goal by Barcelonaโs Irene Paredes when the referee spotted an offside by Frida Maanum. Maanum then went close with a long shot in the 27th that Coll did well to stretch and push over her bar.
Bonmatรญ was the only Barcelona player who seemed to be in the flow before halftime. Her dribble moves through the middle created a few threats and kept Arsenal on guard in defence. Leah Williamson blocked her best shot deep in the box in the 12th.
Barcelona came out of the restart firing.
Pina hit the woodwork with her chipped shot from a sharp angle in the 49th. Bonmatรญ forced goalie Daphne van Domselaar to get low to parry her shot, and Ona Battle bombarded the area with three shots from long range.
But Blackstenius set the tone when she had a golden chance when she stole a ball with only Cata to beat, but the goalie got her leg out to block her effort in the 72nd. The Sweden forward would not be denied a second time.
AP