Jeremie Aliadiere scored twice as Arsenal's second string cruised into the Carling Cup fourth round with an impressive win over West Brom.
Aliadiere enjoyed his second first-team appearance of the season
Aliadiere opened the scoring from the spot after he was brought down by Baggies defender Steve Watson.
The French striker made it 2-0 shortly after half-time from Theo Walcott's astute free-kick.
Jonathan Greening blasted over moments later as the hosts looked to recover, but there was no way back.
Aliadiere's starring role was particularly galling for the home fans as the 23-year-old spent part of last season on loan at their bitter rivals Wolves.
Since returning to Arsenal, the striker has failed to force his way into the first-team reckoning but this performance will have reminded Wenger of his talents.
He and £3.4m summer signing Denilson shone on a night when Walcott sparkled intermittently.
Aliadiere fell under minimal contact from Watson to earn the penalty from which he put the Gunners ahead.
Arsenal's counter-attacking was a joy to watch but they had to wait until after the break to extend their lead.
Walcott, who had just been fouled by Paul Robinson, got to his feet and drove a free-kick straight to Aliadiere, who turned home a first-time shot.
West Brom: Hoult, Watson, Curtis Davies, McShane, Robinson, Chaplow (Gera 58), Quashie (Albrechtsen 69), Greening, Carter (Kamara 38), Ellington, Hartson.
Subs Not Used: Steele, Wallwork.
Booked: Watson, Robinson.
Arsenal: Almunia, Connolly, Senderos, Djourou, Clichy, Flamini, Song Billong, Denilson (Randall 78), Walcott, Adebayor (Traore 24), Aliadiere.
Subs Not Used: Poom, O'Cearuill, Simpson.
Goals: Aliadiere 34 pen, 49.
Ref: M Atkinson (W Yorkshire).