Elye Wahi starred as French side Lens came from behind to shock Arsenal in the Champions League.
Wahi's first-time finish into the bottom left corner from a Przemyslaw Frankowski cross in the 69th minute saw the home side seal a notable success.
The below-par Gunners rode some early pressure from Lens before Gabriel Jesus claimed a 14th-minute opener from a through-ball from Bukayo Saka, who then went off injured.
Lens levelled 11 minutes later as Adrien Thomasson curled a superb finish into the far corner.
As Arsenal suffered their first loss of the season on a difficult night, they suffered another blow before Sunday's crunch Premier League meeting with Manchester City as England forward Saka went off after just 33 minutes.