Saka looked uncomfortable as he limped off the pitch and he pointed to his quad as he spoke to Arteta before heading down the tunnel.
That performance was a real positive for Arsenal but there is now a nervous wait to learn the severity of Saka's injury, which Arteta confirmed was a quad issue.
"We lost Bukayo, who actually was having a great game," Arteta said.
"They are a bit concerned. A player that has to come off with a really sharp pain is never good news but we have to wait and see."
Injury concern: Bukayo Saka
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Saka has started all seven of Arsenal's league matches this season and two of three Champions League games.
"Against Lille he didn't start the game, then he started the game at the weekend," Arteta said.
"It was very early in the game. I don't know, the level of intensity that these games require is something incredible. You could see last game, PSG vs Barcelona, what happened.
"This is man to man, 96 minutes, every action there is no breathing. The quality, the attention, the level that you need is unbelievable. It's the highest level.
"Those things happen unfortunately. It doesn't look good at all but we have to see."