Arsene Wenger's side in fine form and Dutchman leads the way with his 29th goal in this calendar year and two assists as Baggies are easily dispatched
Thomas Vermaelen and Mikel Arteta ensured a further three points in the league for Arsene Wenger's side after Van Persie's opener, in a game which West Brom rarely threatened the home side's goalmouth.
The Arsenal captain returned to the starting XI after being rested for Tuesday's Champions League draw with Marseille, as the Gunners reverted to the same front three that helped defeat Chelsea 5-3 last weekend.
West Brom boss Roy Hodgson was without striker Peter Odemwingie as Simon Cox led the Baggies frontline, with James Morrison and Graham Dorrans returning to the away side's line up in midfield.
The home side failed to trouble Ben Foster in the opening stages, with Brazilian full-back Andre Santos hitting over from a free-kick with the only effort of the opening 10 minutes.Arsenal failed to take advantage with West Brom momentarily down to 10 men after Jonas Olsson had to receive treatment following a collision with Vermaelen, but it was the visitors who threatened on the counter attack, with goalkeeper Wojciech Szczesny diving down to his right to prevent Cox latching onto a dangerous cross.
Yet in the 23rd minute, Arsenal were rewarded for their calm build-up play, as Aaron Ramsey beautifully sliced open the West Brom defence to find Theo Walcott.
The winger tried to slot through Ben Foster's legs, but his attempt was blocked, only for Van Persie to tap in for his 11th goal of the Premier League season, and continue his scintillating form.
Thanks Captain | Vermaelen celebrates Arsenal's second goal with Van Persie
The goal served to buoy both the Arsenal team and the Emirates crowd, as right-back Carl Jenkinson looking lively down the right-wing and provided a number of dangerous crosses.
Five minutes before half-time, the Gunners doubled their lead. After West Brom failed to clear their lines from a corner, Alex Song drifted a cross over to the back post where Van Persie was waiting to cut the ball back across goal for Vermaelen to apply the finish.
Hodgson wouldn't have felt any better about his defence three minutes after the break as they allowed Vermaelen another header at goal unmarked, only for the Belgian to fail to register with the target.
After Chris Brunt missed the Baggies' best chance of the game, volleying well over from the edge of the box, Arsenal almost made it three as Gervinho found Aaron Ramsey in the box before the Welshman turned and dragged a shot just wide of the post.
Tomas Rosicky played a key part in the build-up to the third goal after being introduced as a second-half substitute. The 31-year-old found Van Persie in the box, and the Dutchman's lay-off was perfect for Arteta to sweep into the corner to make it 3-0.
The introduction of Somen Tchoyi for the visitors increased their threat on goal, but the midfielder was unable to guide his shot past Vermaelen as the centre-back blocked his effort, as the home side comfortably saw out the rest of the game.
The result sees Arsenal move up to level on points with Liverpool in seventh place, as the Gunners' resurgence continues.