A strangely shot-shy Manchester City could not find a way through a resolute Southampton side and ended up fortunate to get a draw despite the noisy backing of the home fans at Etihad Stadium.
City, who did not manage a single shot on target until the 90th minute, were sloppy in possession as well as lacking their usual spark in attack and Saints will feel they should have left Manchester with all three points, not just one.
Armstrong had burst into the box after City had again given the ball away cheaply but, despite being first to the ball he was adjudged to have fouled Walker as the City defender attempted a challenge.
That reprieve brought a raucous response from the City supporters, who had already been making themselves heard all afternoon, but they could not galvanise their side.
City thought they had snatched victory right at the end of the 90 minutes when Raheem Sterling followed up after substitute Phil Foden’s header was saved, but he was flagged offside as he converted the loose ball and a lengthy VAR check did not over-rule the decision.
Saints remain winless after sharing the points for the fourth time in five league games, while the draw leaves City three points behind leaders Liverpool.
A lively crowd, but City look lethargic
This was a frustrating 90 minutes for City boss Pep Guardiola, but this time he cannot argue his side’s fans did not do their bit.
Any suggestion that Guardiola’s controversial midweek comments asking more City fans to come to this game might cause a rift between him and supporters were emphatically answered from the off.
The City fans in a near-capacity 53,500 crowd serenaded their manager within 70 seconds of kick-off, singing “we’re glad all over, we’ve got Guardiola” and kept the volume up throughout.
If Guardiola’s intention was to get the crowd going immediately, it worked – but while the crowd was lively, his players looked lethargic for long spells against a well-organised and hard-working Southampton side.
It was far from one-way traffic, either. City had to be wary of Tino Livramento’s frequent breaks forward down the right and Adam Armstrong also impressed with his work on and off the ball.
Southampton manager Ralph Hasenhuttl has not enjoyed his visits to these parts too much in the past few months, with his side shipping 14 goals in heavy defeats at City and Manchester United last season, but a much-deserved point should give him reason to celebrate at last.