Darren Byfield's header took the tie into extra-time
(Arsenal win 9-8 on penalties after extra-time)
Arsenal survived a major scare to go through to the fourth round of the Carling Cup with a penalty-shootout victory over brave Rotherham.
The Gunners eventually triumphed 9-8 on penalties against the Division One side after the score ended 1-1 after 120 minutes at Highbury.
The Gunners - fielding a virtual second string - took the lead after 11 minutes through young French striker Jeremie Aliadiere.
But Rotherham fought back and striker Darren Byfield stunned the home crowd by heading home an equaliser in the 90th minute.
After a sensational shoot-out in which each side took 11 penalties, it was the Premiership team who held their nerve as Sylvain Wiltord scored his second spot-kick after Chris Swailes had seen his effort saved.
With Arsene Wenger resting all of those who started last Sunday's Premiership game at Charlton, he fielded an experimental line-up including four debutants.
Indeed, Spanish Under-17 international Francesc Fabregas - known Cesc - became the youngest player to represent the club at the tender age of just 16 years and 177 days.
Chris Swailes sees his penalty saved by Graham Stack
But it was the experienced French international Sylvain Wiltord, who provided the touch of class which opened up Rotherham's defence.
His neat turn foxed the visitors back four and Kanu was just as composed as he slipped the ball sideways to the lurking figure of Aliadiere, who converted with a minimum of fuss.
Back came the determined visitors, with Stack frustrating them as he rushed from his line to block at the feet of Byfield after the striker had burst clear.
Arsenal appeared to be home and dry but the visitors refused to give up, and with 35 seconds of normal time remaining, Byfield powered home Chris Sedgewick's cross to send the tie into extra-time.
Rotherham's task was magnified 11 minutes into extra time as goalkeeper Mike Pollitt was sent off for deliberate handball just outside his penalty area.
Substitute keeper Gary Montgomery made a stunning save to deny Wiltord before the game went to penalties.
Wiltord's miss was matched by John Mullin and the sides traded successful kicks before Swailes saw his saved and Wiltord made no mistake the second time around to secure victory for Arsenal.
Arsenal: Stack, Tavlaridis, Clichy, Cygan, Hoyte, Fabregas Soler, Aliadiere, Edu, Thomas, Wiltord, Kanu. Subs: Holloway, Spicer, Owusu-Abeyie, Skulason, Smith.
Rotherham: Pollitt, Shaun Barker, Swailes, McIntosh, Richard Barker, Sedgwick, Robinson, Talbot, Hurst, Byfield, Warne. Subs: Baudet, Robins, Mullin, Monkhouse, Montgomery.
Referee: B Knight (Kent).