Tabea Wassmuth moved to Wolfsburg from Hoffenheim this summer, and the 25-year-old striker has been a great success.
With eight league goals, the German has been a strong contributor to Wolfsburg topping the Bundesliga, and in the Champions League her imprint has been even bigger.
Ahead of Wednesday's first quarter-final meeting in the best of two, the home team Arsenal knew that Wassmuth was the player to keep an eye on.
But it did'nt help.
In the 19th minute, she stayed ahead and nodded in 1-0 to the guests - her ninth goal in this year's tournament.
At the beginning of the second half, the Swedish national team striker Stina Blackstenius seemed to have equalized, but the 1-1 goal after a free kick was correctly ruled out for offside.
After a little more than an hour played, Arsenal's uphill was about to become even bigger, but the London team, trained by Swedish Jonas Eidevall, really had the goal frame on their side.
First, Tabea Wassmuth was released, in a suspicious offside position, and dotted inside the post, and in the sequence immediately afterwards, it was Jill Roord who hit the ball in the other post.
Instead, it was Arsenal who would have the last word.
Eidevall replaced Tobin Heath and with a couple of minutes left to play, the American got the chance in a nice free kick position.
It is unclear if Heath meant to pass, or if it was just a failed shot, but the ball ended up perfectly in the step of Arsenal's midfielder Lotte Wubben-Moy who cut to and fixed 1-1.
The return will be played in Wolfsburg next Thursday.