Sometimes the result is the least important thing. A roaring wall of red erupted behind the goal and players and staff on the bench spilled down the sidelines as Arsenal scored late into extra time to retain their ­Continental League Cup title with a win against Chelsea. But it was the news that the midfielder Frida Maanum was ­conscious, stable and talking to the medical staff that really mattered.

Maanum’s off-the-ball collapse deep in injury time as the game stood at 0-0, the player seemingly ­unresponsive and requiring ­oxygen, was hugely concerning. The record crowd of 21,462 fans for the final were worried for the almost 10 ­minutes during which she was being treated. She exited on a stretcher, news arrived that she was stable, and Arsenal charged forward, ­grabbing a 116th-minute winner through Stina Blackstenius.

Related: Arsenal 1-0 Chelsea: Blackstenius hits extra-time winner in Continental Cup final – live

“We just came into the huddle and said: ‘We need to win this game for her,’” Blackstenius said. “It’s just awful to see as a teammate, and as a friend, to see something like that happen.”

There is no love lost between these sides, with Arsenal having earned an emphatic 3-1 win against their London rivals in the final last season to earn Jonas Eidevall his first trophy with the Gunners. The spoils this season have been shared in the league, with ­Arsenal having won 4-1 at the Emirates Stadium in December and Chelsea having ­bitten back with a similarly dominant performance in the return fixture at Stamford Bridge, winning 3-1.

The rivalry was only stoked ­further at Molineux through a spat between Eidevall and Emma Hayes at the final whistle, the latter ­pushing the ­Arsenal manager. Hayes was ­furious about Eidevall’s ­touchline antics ­during a late throw-in as ­Chelsea sought an equaliser, ­saying she would not stand for “male ­aggression” towards players.

Eidevall dismissed the criticism, saying the label was “­irresponsible” before expressing his frustration at Chelsea’s desire to ­suddenly use a new ball for the throw‑in for a quick restart despite blocking a multi-ball system being used ahead of the game.

As Hayes warned before the ­showdown, both league games this season were “over at half‑time” with Arsenal 3-1 up inside 38 minutes and Chelsea 3-0 up by the 32nd minute. “You better show up from the off,” she said. “If you don’t, it can make it a little bit difficult.”

In Wolverhampton, the narrative was different, with both sides alert to the risk of being caught out and the game put beyond them early on.

The Blues had the first chance to go ahead with Lauren James a ­constant threat, pinging a comfortable shot at the goalkeeper Manuela Zinsberger. They had the ball in the back of the net in the 22nd minute too, with Mayra Ramírez’s rasping strike from 25 yards out evading Zinsberger, who perhaps should have done ­better, but a VAR check correctly ruled out the goal, Erin Cuthbert having pushed the ball into the path of the ­Colombian forward with her forearm.

Arsenal weren’t without chances in that period, Cloé Lacasse fired high and wide from distance before the disallowed effort and the Gunners began to stretch the Blues towards the close of the first half.

There was a change for Arsenal at the break to concern Sarina ­Wiegman, the England Women manager, before the international break, with Leah Williamson off and Laia Codina on.

“She had a medical situation and possibly she could have carried on playing but it could have been ­borderline and risk-taking to do that,” Eidevall said. “Hopefully it’s nothing serious.”

The best chance of a transitional second half fell to the effervescent James, who raced free on the left with five minutes of normal time ­remaining, but her effort snuck ­agonisingly wide of the far post.

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Into the sixth of seven minutes of added time Maanum fell, ­collapsing off the ball, landing on her side. There was a lengthy pause while the ­medical team worked on the ­seemingly ­unresponsive player. Maanum was eventually taken on a stretcher down the tunnel.

Shortly after the restart the whistle went for extra time, giving the teams a further opportunity to regroup after a traumatic 10 minutes as news came in from Arsenal that Maanum was in a stable condition.

There was little to separate the sides in extra time, Blackstenius blazed over but would get another, more difficult, chance with ­minutes to spare. Caitlin Foord, on as a ­substitute, evaded challenges on the left before she pulled the ball back for Blackstenius, who turned and fired in. The wall of red behind the goal erupted and the party began on the final whistle in style.

“The fans have been pretty ­incredible all season, but it felt ­special,” Beth Mead said. “There were a lot of Arsenal fans out there today. Very happy to get the win for them and to celebrate in front of them all.”