Nicklas Bendtner scored for Arsenal in more than two-and-a-half years - well sort of - from the penalty spot in a shootout as the North London side went through 4-3 on penalties against West Brom in a terse Capital One cup third round encounter at the Hawthorns.
Nacho Monreal scored the winning goal from the penalty spot, after Craig Dawson and Morgan Amalfitano had missed for West Brom, to take the Gunners through to the fourth round where they will host Chelsea in what promises to be a cracking game.
Steven Reid, Markus Rosenberg and James Morrison scored for the Baggies in the shootout, with Bendtner, Kristoffer Olsson, Chuba Akpom and Nacho Monreal making up for Serge Gnabry's miss for the Gunners.
Thomas Eisfeld had put Arsenal in the lead just past the hour mark in normal time, before Saido Berahino forced the game into extra time with the equaliser.
Arsene Wenger put out a young side against West Brom, sprinkled with a few established players, with the likes of Isaac Hayden, Thomas Eisfeld, Ryo Miyaichi, Serge Gnabry and Nicklas Bendtner given a chance to impress.
However, it was not the usual flowing Gunners on view, though, with the match very much a cagey one as both sides struggled to find any sort of forward momentum.
Arsenal's best chance came when the ball nearly snuck in off a corner towards the end of the first half, with Steven Reid then grazing the crossbar with a freekick at the other end as a rather tame half came to a close.
Eisfeld struck over after some good work from Carl Jenkinson as Arsenal started the second half in search of that elusive goal.
Lukasz Fabianski was asked to make the first real save of the night off a clean long-ranger from Youssouf Mulumbu as West Brom started to grow in confidence.
However, it was Arsenal that struck the opener on 61 minutes with a certain forgotten Dane picking up the assist.
Gnabry found Bendtner in space outside the box, with the Dane then picking out a nice through ball to Eisfeld, who took a perfect first touch before nonchalantly slotting it past the West Brom goalkeeper.
Arsenal, though, just could not hang onto their lead as West Brom struck back with an equaliser ten minutes later, through the ever-impressive Berahino.
A corner was initially cleared from the danger area, but a hooked ball back in caught Arsenal unawares with Berahino, who scored a hat-trick in the previous round, sneaking in to head home.
Wenger made a couple of changes in search for the winner, bringing on striker Chuba Akpom and attacking midfielder Kristoffer Olsson for Eisfeld and Hayden respectively.
A wicked Jenkinson cross in stoppage time nearly unlocked the door for the second goal for Arsenal, but West Brom held on as the match headed into extra time.
Bendtner had a golden opportunity to grab the headlines when Gnabry put him through with a glorious through ball; but the Dane - probably thinking of the headlines he was going to make -- hesitated and West Brom defender was allowed to make a last-ditch tackle.
Substitute Hector Bellerin took a couple of potshots from distance, with Amalfitano at the other end coming desperately close to finding the winner, with his thunderous strike smashing he crossbar.
Markus Rosenberg then somehow failed to find the goal as Scott Sinclair missed another chance with West Brom looking like the side most capable of scoring from open play.
However, the match went into the penalty shootout, where Arsenal held their nerve better than West Brom.