The Gunners broke the deadlock in the seventh minute when Ezri Konsa turned home a corner delivered by Martin Odegaard. The scrappy finish marked Konsa's first goal for the club and Arsenal's first set-piece strike in the league this season.
Arsenal built a reputation for their effectiveness in such situations last term, scoring 29 goals from corners, free-kicks and penalties during their title-winning campaign. Arteta believes his team can return to that level of productivity.
Gabriel secured all three points in the second half, rising to head home a cross from Ben White and complete the 2-0 victory.
The result extended Arsenal's impressive start to the campaign, with the north London side claiming seven wins from their opening eight league fixtures.
"I'm sure that's going to unlock something and that belief of the players," manager Arteta said. "So they are really convinced.
"You have to see them when we train the level of attention and how much they believe in what we do and what Nico [Jover, set-piece coach] does as well.
"There's no question about that, but at the end he has to come through and he has to make the difference and we know that that is a massive welcome for us."
They also benefited from Manchester City's first defeat of the season, as the reigning champions fell to a 2-1 loss away to Aston Villa in Saturday's lunchtime encounter.
Arsenal are now level with City on 21 points at the top of the standings but occupy second place because of their inferior goal difference. The victory also offered a welcome response to their 2-2 draw away to Bayern Munich in the Champions League.