Lacazette's goal was his sixth of the season
The Gunners were all but through before kick-off, with the hosts needing to win 5-0 to prevent the visitors from going through to the knockout rounds - a result that looked even more unlikely after a first half Arsenal edged.
However, Samuel Bastien put the hosts ahead just after the restart when his shot deflected off Sokratis and beyond the wrong-footed Emiliano Martinez.
The goal boosted the hosts but visibly knocked the fragile confidence of the Arsenal players, who became even more nervy when Standard Liege got a second as Selim Amallah's strike from inside the area flew into the far corner via a slight deflection off Konstantinos Mavropanos.
It set things up for a tense final 20 minutes as the hosts pursued an unlikely result but Alexandre Lacazette settled the Gunners' nerves when he converted a bullet of a header.
Bukayo Saka then equalised with 10 minutes to go, curling a neat finish into the corner to secure the draw Arsenal needed to top Group F.