10-man Arsenal held off a determined challenge from Sunderland to win 1-0 at the Stadium of Light.
A strike from Santi Cazorla on 35 minutes proved to be enough for Arsene Wenger's side despite being down to 10 men for much of the second half after Carl Jenkinson's dismissal.
Martin O'Neill's men pushed hard for a winner but found Arsenal's rearguard impenetrable in a frenetic finish to an entertaining game.
The Gunners started lively with Theo Walcott, looking for his 12th Premier League goal of the season, forcing two early saves from Belgium international keeper Simon Mignolet.
Arsenal continued to have the better of the play and they almost took the lead when Olivier Giroud fizzed a shot just past Mignolet's far post after some neat build-up play from Jack Wilshere and Cazorla.
Sunderland had Mignolet to thank for keeping them level just after the half-hour mark when making a flying save from Ramsey but he could do nothing on 35 minutes to prevent Cazorla giving Arsenal the lead.
Wilshere carried the ball forwards before finding Walcott and the England winger's slipped the ball to the Spanish international who thumped home a low strike to give the Sunderland keeper no chance.
The visitors almost doubled their lead on the stroke of half-time when Walcott fired narrowly wide from the edge of the area.
Worryingly for the north Londoners, Wilshere was forced off with an injury to his right leg after a heavy challenge and it seemed to disrupt Arsenal's rhythm which was worsened by right-back Jenkinson's dismissal on 61 minutes for a second yellow card after a silly lunge on Stephane Sessegnon.
The Black Cats began to mount some pressure with Steven Fletcher wasting a golden chance when sent clear but Arsenal served note they weren't finished as an attacking force when Walcott struck a post on the counter.
The pressure continue to mount on the visitors' goal with Woijcech Szczesny pulling off a super one-handed save from substitute Danny Graham's volleyed effort before Titus Bramble missed a gilt-edged chance after a goalmouth scramble following a corner.
However, Arsene Wenger's side held on for a vital three points in their battle for a Champions League qualification spot and the smile on the manager's face afterwards spoke volumes for the potential significance of the win.