A shocking dive by Santi Cazorla set Arsenal on course for an easy victory against woeful West Brom at the Emirates Stadium.
The Spaniard threw himself to the ground to win the Gunners a controversial penalty from which Mikel Arteta gave them a 26th-minute lead.
And a second spot-kick from Arteta made it 2-0 on 64 minutes after Chris Brunt fouled Alex Oxlade-Chamberlain, although Albion felt the Arsenal youngster had shoved Goran Popov in the build-up.
The visitors could feel aggrieved about the goals but they could have no complaints about the result following a dreadful display that ended in a third successive defeat.
Arsenal had the better of the opening stages but failed to fully test Boaz Myhill.
They went close early on when Gervinho rolled a shot just wide after Albion failed to deal effectively with a Cazorla corner.
And Cazorla sent a volley over the bar after Alex Oxlade-Chamberlain sprinted down the right and delivered a fine cross.
Chris Brunt went even closer, however, when he ended a rare Albion counter-attack with a curling right-footed shot that flew just past the angle of post and bar.
But it was the Gunners who took the lead in controversial fashion when Cazorla turned smartly in the box to draw a challenge from Reid but then threw himself to the ground despite replays showing the Baggies defender had made no contact.
The visitors were furious but they had to watch Arteta fire a cool penalty down the middle and away from the diving Myhill.
It should have been 2-0 to the hosts seven minutes before the break as Gervinho beat the Baggies’ offside trap to burst to the byline on the left.
He pulled the ball back to the far post, where a sliding Jack Wilshere diverted the ball wide with the goal at his mercy.
Just before the interval Oxlade-Chamberlain sent an overhead kick over the bar from another Cazorla corner.
Eight minutes into the second half a messy passage of play in the Baggies box ended with Oxlade-Chamberlain volleying against the crossbar.
And Gervinho then missed two good chances to double the lead for the hosts, first when he headed wide from a teasing Kieran Gibbs cross and then when he failed to make contact five yards out after a flick by Olivier Giroud deflected into his path.
But the second goal came on 64 minutes from another penalty.
The Baggies were convinced Oxlade-Chamberlain had shoved substitute Goran Popov on his way into the box but there was no doubt this time that he was chopped down by Chris Brunt.
Arteta again made no mistake with his spot-kick.
Albion threw on all three substitutes in a bid to turn around their fortunes but they were unable to alter the course of the game.
Their only chance came in the dying moments when Romelu Lukaku glanced a header wide from a Brunt free-kick.
In the closing moments Gunners substitute Lukas Podolski was guilty of a shocking miss when he blazed over from six yards after a fine run by Jack Wilshere.
By Steve Madeley