A Philippe Senderos header after four minutes and a cool finish in injury time by Emmanuel Adebayor, who has now scored in nine consecutive games, were a fair reward for Arsenal’s dominance against a side who had lost only two of their previous 12 away games.
With 12 matches remaining, Arsenal have 63 points to the 58 of Manchester United, who lost 2-1 at home to Manchester City on Sunday. Chelsea are three points further back on 55 after their goalless draw with fifth-placed Liverpool (44).
Blackburn, who went into the game hard-hit by injuries and suspensions, remain ninth.
Arsenal went ahead when Eduardo da Silva swung in a corner and Switzerland captain Senderos rose unchallenged to head firmly home.
Blackburn ’keeper Brad Friedel saved well with his legs from Mathieu Flamini after 26 minutes as Arsenal looked in control, though Benni McCarthy could have levelled when he glanced a header wide after 40.
Arsenal looked re-energised after half-time and the tireless Alexander Hleb hit a post within four minutes while Friedel saved three times from Adebayor.
The home team almost seemed more keen on trying one more intricate pass instead of having a shot on goal and when Cesc Fabregas went clean through seven minutes from time he tried an elaborate finish and put the ball over the bar.
It fell to Adebayor to show the way as the Togo striker collected a Hleb pass before producing a terrific finish for his 22nd goal of the season. Arsenal now take on Manchester United in the FA Cup this weekend followed by AC Milan in the Champions League next week.