Saka made it four with a composed finish, before Aubameyang completed his hat-trick with a wonderful strike from just inside the box.
As such expect Allardyce to reprise the 10 behind the ball tactics he deployed at Anfield.
The Gunners took the lead just past 20 minutes through Tierney, who beat his defender twice, cut into the penalty area and smashed an unstoppable strike past West Brom's Sam Johnstone to put his side in front.