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Reading's lowly league position was reflected in their school-yard defending as Arsenal cut through the home team at will to open up a four-goal lead before the hosts briefly threatened to make a game of it late on.
Germany forward Lukas Podolski put Arsenal ahead after 14 minutes while Cazorla scored twice in the first half and once after the break as the visitors ran riot.
Adam Le Fondre grabbed what looked like a consolation before Jimmy Kebe briefly stirred the home fans to believe in an unlikely comeback before Theo Walcott wrapped up the match.
Arsenal now have 27 points from 17 games, two behind rivals Tottenham Hotspur in fourth and 15 behind leaders Manchester United. Reading stay bottom with nine points.
Arsenal were looking to rebound from their humiliating League Cup exit at the hands of fourth tier Bradford City last week and took the lead when Podolski took a touch and fired left-footed into the net for his fifth Premier League goal of the season.
The lead was almost doubled eight minutes later when Walcott, handed the central striking role he craves, sprung the offside trap but his low shot was parried by the feet of Reading keeper Adam Federici.
It was only a matter of time before Arsenal grabbed a second and on 32 minutes Podolski turned provider, darting down the left flank and curling in a cross that found Cazorla arriving in the centre unmarked to head past Federici.
Cazorla's second was another example of poor Reading defending.
Full back Kieran Gibbs headed a Podolski cross back into the danger zone and Cazorla found space to swivel in the area and score with a volley that bounced up off the ground and into the net.
The Spaniard's hat-trick arrived 14 minutes after the break when midfielder Jack Wilshere fed Podolski who crossed from the left and Cazorla swept home from close range.
The last time these two teams met was the extraordinary League Cup tie in October when Arsenal recovered from a 4-0 deficit to win 7-5 in extra-time.
Memories of that improbable comeback were stirred as Reading briefly threatened.
Le Fondre grabbed a goal back on 66 when he rounded Arsenal keeper Wojciech Szczesny and tapped in before Kebe latched onto a throughball and slotted home with 19 minutes still to play.
Walcott squashed any hopes of a home comeback, however, when he cut inside his marker to add a fifth 10 minutes from time.