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 went off injured with a muscular problem.
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 were dealt another blow before Sunday’s crunch Premier League meeting with Manchester City as England forward Saka went off after just 33 minutes.
But Lens were worthy of a win that took them to the top of Group B on four points, with Mikel Arteta’s side second on three.
It was a tough night for the Gunners who looked off the pace as a run of nine Champions League group stage games unbeaten was ended by a buoyant Lens.
Sloppy in defence, Arsenal struggled to create clear-cut chances.
Lens goalkeeper Brice Samba made a good reaction save to deny Takehiro Tomiyasu from a Gunners corner, but was not tested enough.
Saka injury adds to sloppy Arsenal’s woes
Arsenal will look to bounce back in the Champions League when they travel to Sevilla in three weeks’ time, while Lens host PSV.
However, the departure of Saka will be the biggest concern when the dust settles.
He was doubtful for the 4-0 win against Bournemouth at the weekend but started before being withdrawn after 76 minutes. Saka was passed fit for this match, but went off in discomfort.
Before his substitution, Saka showed his quality once more by providing the assist for Jesus’ strike and become the first player to record five goals and five assists in all competitions this season for a team in Europe’s big five leagues.
He later emerged around the hour mark and sat on the bench with his team-mates to watch the rest of the match.
But, while Arteta said he had no regrets, questions will be asked about his decision to risk Saka, especially if he is absent when champions City visit the Emirates on Sunday.