Aresnal got a huge boost in their quest for a spot in the Champions League when they beat Manchester United by 2-0 at the Emirates Stadium in London on Sunday.
After a barren first-half Granit Xhaka put Arsenal ahead with a powerful shot from 30 yards in 54th minute before Danni Welback doubled the margin heading home an Oxlade-Chamberlain chip three minutes later.
Earlier, James Milner missed a penalty as Liverpool were held to a 0-0 home draw by Southampton in a blow to their hopes of finishing in the top four and securing a place in next season’s Champions League.
Phillippe Coutinho returned from the leg injury that saw him limp out of Monday’s 1-0 win over Watford, but the Reds struggled to spark offensively against Southampton’s resolute defence.
The hosts were handed a lifeline in the second half when referee Robert Madley pointed to the spot after Southampton defender Jack Stephens handled the ball in the box, but Fraser Forster got down smartly to his right to keep out Milner’s spot kick.
Forster also tipped substitute Marko Grujic’s late header over, leaving Liverpool third in the table on 70 points, a point clear of fourth-placed Manchester City, who have a game in hand.