Goals by England defender Sol Campbell and Frenchman Robert Pires at the end of each half took Arsenal to 39 points, two ahead of Chelsea, who cruised to a 2-0 victory over Aston Villa at Stamford Bridge.
Third-placed Manchester United (35 points) travel to Blackburn Rovers on Sunday, when Everton, in fifth on 32, also face sixth-placed Liverpool.
Newcastle United moved into fourth, also on 32 points, following their 2-0 home win over Fulham.
West Ham United remained rooted to the bottom and still searching for their first home win of the season after a 1-1 draw against second-last Bolton, whose striker Michael Ricketts cancelled out Ian Pearce's early effort.
Fellow-strugglers West Bromwich Albion netted two goals in a match for only the second time this season as Danny Dichio and Jason Koumas put them 2-0 up against Sunderland, only for Kevin Phillips to score twice and earn a point for the visitors.
Leeds United looked set for a rare home win thanks to a Harry Kewell goal, but Fabrice Fernandes earned a point for Southampton at the death with a 40-metre free kick that evaded everyone, including Leeds keeper Paul Robinson.
Birmingham City drew 1-1 at home with Charlton Athletic in the day's other game, while Tottenham Hotspur visit Manchester City on Monday to complete the weekend programme.
Arsenal had lost four of their last nine league games and looked short of confidence in the early stages against Middlesbrough.
But the visitors' hopes of holding out for a point took a severe dent on 22 minutes when combative midfielder George Boateng was carried off after falling awkwardly.
Arsenal made the breakthrough in first-half injury time when Campbell, who had earlier hit the post, stooped low to head home a curling Giovanni van Bronckhorst free kick.
Middlesbrough, who had failed to score in six of their previous eight away games, did improve slightly after the break but never looked likely to repeat their 3-0 win at Highbury in 2001 - their only success at the ground in half a century.
SECOND BOOKING
Brazilian
Pires then scored the goal Arsenal's dominance deserved with an excellent low shot in the last minute.
"We were focused, determined and patient when needed and overall I'm very happy," Arsenal manager Arsene Wenger told Sky Sports. "I felt that the attitude was right and the concentration for 90 minutes was right.
"Middlesbrough came out more positive for the first 10 or 15 minutes after halftime but we defended well and from then on I thought we would win the game and it looked always like we could score."
Chelsea's, whose 11-game unbeaten run came to an end on Tuesday with League Cup defeat at Manchester United, almost fell behind after three minutes on Saturday when Villa defender Olof Mellberg hit the crossbar.
But the Londoners, without the rested Gianfranco Zola, slowly took control and Eidur Gudjohnsen took advantage of a rare start to drive home the opening goal after 42 minutes.
BOUNCED OVER
Chelsea doubled their lead early in the second half when Frank Lampard's cross bounced over Peter Enckelman after Gudjohnsen's presence wrong-footed the Villa keeper.
Villa remained the only premier league team without an away victory this season having mustered only two goals in nine games on their travels.
Newcastle's terrific home form continued when they made it eight wins from nine games against a lacklustre Fulham.
Nolberto Solano put the hosts ahead in the eighth minute with a cushioned lob after Fulham goalkeeper Edwin van der Sar sent a clearance straight to him.
Newcastle were handed a controversial penalty at the start of the second half which Alan Shearer blasted high and wide, but after the sending-off of Fulham's Pierre Wome, striker Craig Bellamy sealed the points with a deserved second goal for Newcastle.
© 2026