Arsenal failed to win at home in the Premier League for just the second time this season when it drew 1-1 with Birmingham on Saturday.
Emmanuel Adebayor put Arsenal ahead with a penalty kick in the 21st, but Garry O'Connor equalized early in the second half with a deflected header.
Chelsea is just four points behind Arsenal after extending its unbeaten streak at Stamford Bridge against Tottenham to 20 games with a 2-0 win, while Liverpool lost more ground on the leading teams with a 1-1 draw at Middlesbrough that will increase the pressure on manager Rafa Benitez.
Manchester United could take the lead later Saturday if it beats visiting Newcastle, which is without a fulltime manager following the midweek departure of Sam Allardyce.
Arsenal was awarded a penalty kick when Stephen Kelly tackled Eduardo da Silva from behind in the area, even though the defender seemed to have got a touch on the ball.
Adebayor hit the kick to goalkeeper Maik Taylor's left for his 13th goal of the season.
Birmingham was denied a penalty of its own when Philippe Senderos brought down Olivier Kapo in the area, but drew level three minutes after halftime when O'Connor headed a corner by former Arsenal striker Sebastian Larsson into the net off a deflection from Cesc Fabregas.
Birmingham is just the second team _ after Manchester United _ to avoid defeat at Arsenal in the Premier League this season. Liverpool was saved from defeat by a 71st-minute goal from Fernando Torres, the Spain striker's 17th of the season. Middlesbrough had taken the lead in the 26th when George Boateng collected a header from Tuncay Sanli and shot into an empty net. Benitez took off a defender and brought on winger Ryan Babel at halftime to try and salvage a result, and Andriy Voronin and Torres soon had chances.
Liverpool could have fallen further behind when Jeremie Aliadiere rounded goalkeeper Pepe Reina outside the area but could only put the ball across the empty goal.
Gary O'Neil then missed two chances for Boro before Torres scored with a 25-meter (yard) shot.
Liverpool retook fourth place from Manchester City but is now eight points behind third-place Chelsea.
Liverpool was joined on 39 points by city rival Everton, which beat visiting Manchester City 1-0 through a 31st-minute goal from Joleon Lescott.
Aston Villa also has 39 after its 3-1 win over visiting Reading. Tottenham's hopes of a first win at Chelsea since 1990 were boosted by the absence of Didier Drogba and Salomon Kalou at the African Cup of Nations, and Andriy Shevchenko, Frank Lampard and John Terry through injury.
But Spurs, who drew 1-1 at Arsenal in a midweek League Cup match, fell behind in the 19th when Juliano Beletti was allowed to advance from defense unchallenged and hit a 30-meter (yard) shot into the top of the net.
It was Beletti's first goal at Stamford Bridge and Chelsea's only score until 10 minutes from the end when winger Shaun Wright-Phillips hit a low shot into the corner.
Chelsea improved to 47 points, 23 more than Tottenham, which is still mired in midtable despite improved performances under coach Juande Ramos.
West Ham rallied to a 2-1 win over next-to-last Fulham, while Wigan edged away from the relegation zone with a 1-0 win at last-place Derby, which has seven points.
Wigan now has 20, three more than 18th-place Sunderland, which hosts Portsmouth on Sunday.
Bolton hosts Blackburn in Sunday's other game.