Di Canio was sent off in injury time, having had to watch Wales international Ramsey blast home a 67th-minute volley and then convert Olivier Giroud's pass nine minutes later to kill off the resurgent Black Cats.
The home side were left fuming after having what they believed was a legitimate equaliser chalked off, when Arsenal's lead was only 2-1.
Three minutes after Ramsey had put the visitors ahead for the second time, striker Jozy Altidore outmuscled Gunners skipper Bacary Sagna as the defender attempted to wrestle him off the ball.
The powerhouse United States international brushed off the Frenchman and stabbed the ball past goalkeeper Wojciech Szczesny and over the line.
Referee Martin Atkinson had already blown for a foul and called play back, much to the fury of the home fans.
The disallowed goal punctured the momentum the home side had built up after a poor start.
Ozil's virtuoso first-half performance was a thing of beauty, the ?43million German setting up Giroud to give Arsenal an 11th-minute lead and creating two gilt-edged chances for Theo Walcott, both of which went begging.
But the Black Cats, for whom central defender Modibo Diakite hit the bar three minutes after Giroud's strike, staged an impressive revival after the break.
They levelled within four minutes of the restart when half-time substitute Craig Gardner converted from the penalty spot after Adam Johnson had been tripped by Laurent Koscielny.
Source: PA
Source: PA