The defender was last week lavished with praise after a man-of-the-match display on his Gunners debut against Crystal Palace, but had a tougher time of it against Leicester on Saturday.
With Arsenal cruising, Saliba's poor attempt at heading a Leicester cross behind instead beat Aaron Ramsdale and nestled inside the near post for an own goal.
The Arsenal fans did not care, though, and instead of bemoaning the mistake they cheered and applauded the defender, and it did not go unnoticed by Arteta.
"What [the fans] did with Saliba after the own goal is something I’ve never seen anything like that in my career," he told reporters. "I think it lifted Willy’s confidence."
He added: "I'm more happy today [with Saliba] than I was last week with Palace because of how he reacted to the own goal."