Ivory Coast international Gervinho, such a frustrating figure for the Gunners, set the hosts on their way after 11 minutes.
However, despite dominating possession, it was not until the start of the second half where the crucial breakthrough came again, this time Santi Cazorla sweeping home.
Olivier Giroud added a third following a quick break by Gervinho. Reading - who squandered a 4-0 lead against** **Arsenal in their home Capital One Cup tie earlier this season - started positively, as Mikele Leigertwood headed wide from a corner.
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Increasingly cloudy with drizzly rain tonight. A cloudy start on Monday but brightening up with plenty of sunny spells in the afternoon.
The grass pollen risk will rise to high during warm, dry weather.
Cloudy with patchy rain and drizzle this evening. Mild tonight, then dry with plenty of sunny spells tomorrow.