Mariona Caldentey scored a stoppage-time penalty as Arsenal narrowly avoided a frustrating draw against Danish side HB Koge in their opening Women’s Champions League campaign.

The Gunners dominated possession but struggled to turn their control into clear-cut chances against a Koge side featuring several part-time players.

Arsenal thought they had taken the lead when Chloe Kelly’s clever outside-of-the-boot effort beat goalkeeper Alberte Vingum, only for VAR to rule out the goal after determining that Stina Blackstenius had been in an offside position and in the goalkeeper’s eyeline.

Despite their dominance, Arsenal repeatedly lacked the cutting edge required in the final third, while sloppy possession allowed the Danish visitors opportunities to press and win the ball back.

Koge’s defensive resilience was reflected in the animated celebrations of manager Kristian Morch at half-time, with his side having successfully frustrated the hosts for long periods.

Arsenal boss Renee Slegers had made eight changes from the team that drew 1-1 with Manchester United at the weekend and attempted to alter the pattern of the game at the interval by bringing on Alessia Russo for Blackstenius.

However, Russo’s introduction did little to change Arsenal’s fortunes, with the second half largely following the same pattern as the first.

The Gunners continued to dominate the ball but struggled to create genuine openings, leaving them in danger of dropping points in their opening European fixture.

Arsenal eventually found their breakthrough in stoppage time when Selina Cerci was brought down inside the penalty area.

Caldentey stepped up to take responsibility from 12 yards and made no mistake, although Vingum got a hand to the effort.

The goalkeeper could not keep the ball out, allowing Arsenal to escape with a narrow victory and three points from a game in which they had been made to work for almost everything.