Arsenal's tough start to the season continued as Leah Williamson gave away a freak penalty late on to see Paris FC come from two goals behind to draw 2-2 with the Gunners.
Renee Slegers' side had put themselves in a commanding position thanks to both Alessia Russo and Georgia Stanway notching their first goals of the season.
However Clara Mateo and a spot kick from Maeline Mendy after Williamson had picked up the ball from a goal kick, saw the hosts turn the game around and snatch a point from the tie.
The collapse puts more scrutiny on Slegers after just one win from the opening four WSL games prior, and the 37-year-old chose not to attend her post-match press conference.
Arsenal's main issue this season had been a lack of firepower in front of goal - and they were toothless for much of the first 45 minutes. That was until Russo combined with Stanway before rediscovering her clinical edge with a fine finish from the edge of the box.
Shortly after the break, it was Stanway's turn to celebrate. The former Bayern Munich midfielder was found unmarked inside the six-yard box and smashed home a volley to net her first goal since joining the club in the summer.
At that point, it seemed like there was only one winner. However, Arsenal failed to push the initiative in search for a third and were made to pay. First, Paris captain Mateo broke away on the counter before rounding past goalkeeper Misa and slotting into an empty net.
Then, with three minutes of normal time remaining, disaster struck. Having won a goal kick, Misa passed the ball to Williamson, seemingly for the Lioness to take the kick herself.
However, the referee had blown the whistle to resume play, so when Williamson picked up the ball to put it into position for herself to restart the game, Iuliana Demetrescu pointed to the spot.
Substitute Mendy fired into the bottom corner to complete the comeback and salvage a point for the hosts, condemning Arsenal to another disappointing result.
'It should not have been a penalty, but we will learn'
Arsenal assistant coach Aaron D'Antino standing in for Renee Slegers in post-match press conference:
"If we're looking at what we can control, it's just passing the ball to Leah. From what I remember seeing, the ball was still rolling and she was moving it to Leah for her to take the goal kicks as we normally do. So maybe the learning in that is how we get the ball to Leah, so we don't put ourselves in that situation.
"But yes, like I said, as far as we're concerned that's not [a penalty]. We haven't taken a goal kick, there's no advantage gained by Leah stopping the ball. But as an example of refereeing decisions, we just can't put ourselves in that situation in the first place."
Russo: We let Paris back in before penalty mistake
Arsenal striker Alessia Russo speaking with Disney+:
"No [I didn't see us not winning the game]. It was a mistake. Obviously it wasn't intended at all. It's football, sometimes things like that happen. Unfortunately, it wasn't ideal but we move on.
"We let them come back into the second half way before that moment. We are disappointed but there were some really good things tonight."
On moving one behind Fran Kirby's English record of Women's Champions League goals:
"I had no idea that was even a record. It's nice. I'm really happy to have scored tonight because it's been a bit of a tough period. I'll just keep working hard and see what happens. Most importantly we keep building for Sunday and then the rest of the Champions League."
