Despite a superb early goal by Granit Xhaka, Arsenal were held to a 1-1 draw by Southampton on Sunday.
The result moves Arsenal to 28 points from 11 games, two ahead of second-placed Manchester City.
Southampton currently sits in 15th place with 12 points from 12 games.
In the first 15 minutes, the visitors appeared unstoppable, launching wave after wave of attacks on the home goal.
They were rewarded with an excellent opener from Xhaka, who also scored the winner in their Europa League win over PSV Eindhoven in midweek.
Xhaka thundered into the roof of the net after Bukayo Saka's flick set right-back Ben White away down the right flank.
The Swiss international had not scored with his right foot in his first 263 games for the North London club, but has now scored two in his last two.
"We started well and should have scored more, but we're only human and it's tricky," White said, adding that they were disappointed with their performance in the second half.
"We were sloppy with the ball and didn't win duels." It was the inverse of the first half."
As Arsenal threatened a second goal, home goalkeeper Gavin Bazunu made a fine save from Gabriel Jesus' excellent acrobatic shot.
Jesus had another chance to score when Martin Odegaard sent him clear, but Mohamed Elyounoussi came up with a brilliant block.
Southampton must have been relieved to be only 1-0 down at the break, but they came out firing in the second half.
They were deserving of their equalizer, perhaps taking advantage of an Arsenal side that appeared tired from their midweek exertions.
On 65 minutes, a quick counter-attack paid off when Elyounoussi slipped the ball into the path of Armstrong, who finished calmly past goalkeeper Aaron Ramsdale.
Following that, the home team appeared more likely to score, but they only created half-chances.
They will almost certainly see it as a well-earned point, and perhaps a springboard to better things this campaign.
"It was always going to be a difficult game, (and) it didn't start off well." But getting a point is fantastic for us," goalkeeper Armstrong said.
"We quickly changed the shape and set deeper to limit their chances." We knew we could be dangerous on the counter-attack."
Arsenal host Nottingham Forest on Sunday, while Southampton visit Crystal Palace on Saturday.
REUTERS