Alexis Sanchez' hat-trick helped Arsenal end Leicester City's unbeaten start to the season as they claimed a comprehensive 5-2 Premier League victory at the King Power Stadium.
The Chile forward had not scored in 2015-16 prior to Saturday's clash, but he was on top form as Arsene Wenger's men ultimately cruised to victory.
Leicester, who had to come from behind in their last four league fixtures prior to Saturday's clash, took the lead this time round through Jamie Vardy's fourth goal in as many league games 13 minutes in.
But Arsenal had the lead when Sanchez nudged in from close-range, after Walcott's 12th goal in his last 13 Premier League starts had cancelled out Vardy's opener.
Sanchez then capped a stunning Arsenal move to head in his second after the interval, before claiming his hat-trick with a sumptuous strike from distance.
Vardy's sixth goal of the season rounded off a fine individual performance, only for Olivier Giroud to add another for Arsenal in stoppage time.
Leicester would have been behind early on if not for a goal-line clearance from Ritchie De Laet, but responded well and could have gone ahead themselves as Jeffrey Schlupp drew a fine save from Petr Cech.
Moments after hitting the post with a scuffed effort, Vardy lit up the game as he latched onto Danny Drinkwater's raking pass and drifted in from the left to curl a superb finish beyond Cech.
The England man was just inches away from second five minutes later, his header clipping the top of the crossbar.
And Arsenal hurled themselves level from the resulting counter-attack, Santi Cazorla sliding through to Walcott, who raced in behind Robert Huth to squeeze home a finish off the left-hand upright.
Wenger's men completed the turn-around shortly after the half-hour as Hector Bellerin's drilled cross was helped on by Walcott, with Sanchez on hand to tuck home from close-range.
Leicester captain Wes Morgan should have restored parity on the stroke of half-time, but he failed to apply the finish after connecting with Marc Albrighton's pinpoint free-kick.
Arsenal's goalscorers combined well after the interval, Sanchez latching onto Walcott's flick, but his strike was deflected wide.
Sanchez did double his tally just prior to the hour-mark, ghosting in from the right flank to beat Leicester's offside trap and head in past the despairing reach of Kasper Schmeichel.
And the Chile star had his hat-trick with nine minutes remaining, floating inside from the left before firing into the bottom-left corner from 25 yards.
Although Vardy curled in a second for the hosts, Arsenal substitute Giroud swept in from Nacho Monreal's cross to add a fifth, as the visitors doubled their tally of league goals for the season in one outing.
