The Gunners won 2-0 at bottom side Aston Villa to move to 33 points from 16 games, but Leicester could leapfrog them with victory over reigning champion Chelsea in Monday night's game.
The easy victory capped a triumphant week for Arsene Wenger's men, who booked a place in the last 16 of the Champions League last Wednesday with a 3-0 win over Olympiakos in Greece, with Olivier Giroud scoring a hat-trick.
Giroud was on target again at Villa Park after only eight minutes.
Referee Kevin Friend belatedly pointed to the spot after Theo Walcott had been pulled back and bundled over by Alan Hutton, the Frenchman easily converting the penalty kick.
It was his 50th Premier League goal and Arsenal might have added more before a counter attack late in the first half saw Mesut Ozil find the excellent Aaron Ramsey for a simple finish.
Villa improved after the interval but Petr Cech was little troubled in equaling the EPL record for clean sheets, his 169th in 349 appearances for the former Chelsea goalkeeper.
It left Arsenal a point clear of Manchester City, last-gasp 2-1 winners over managerless Swansea Saturday, and Leicester.
Manchester United later needed a win at Bournemouth to join the group on 32 points, but instead slumped to an upset 2-1 defeat to the newly promoted side.
Bournemouth, which stunned Chelsea last weekend,
took the lead when a Junior Stanislas corner found its way into the visiting net.
United fought back and Anthony Martial wasted a great opportunity before Marouane Fellaini bundled home the equalizer just before halftime.
Joshua King, a former youth player at Old Trafford, scored the winner against his old side as he converted from a Matt Ritchie corner to complete a dismal week for Louis van Gaal's team.
Beaten by Wolfsburg in midweek to be eliminated from the Champions League, the Red Devils at least remained in fourth after Tottenham Hotspur was stunned 2-1 at home by Newcastle in Sunday's late kickoff, ending its 14-match unbeaten run.
Eric Dier put Tottenham ahead just before halftime with a near post header, but the home side lost impetus after the break with substitute Aleksandar Mitrovic bundling an equalizer.
Fellow replacement Ayoze Perez scored the winner in injury time, his shot eluding Hugo Lloris.
A second straight win lifted Newcastle out of the relegation zone and like Bournemouth moving above Chelsea, which is just one point above the drop zone ahead of Monday's visit to Leicester.
Sunday's other game saw Liverpool fight back from 2-1 down at home to West Bromwich Albion with Divock Origi's deflected late shot rescuing a point for Jurgen Klopp's team.