His first-team debut came as an 85th-minute substitute in the League Cup match against Rotherham United on 28 October 2003. During extra time he attempted to chip Rotherham goalkeeper Mike Pollitt, who handled the ball outside his penalty area and was sent off. With the score 1–1 after 120 minutes the game was decided in a penalty shootoutthe first ever shootout featuring Arsenal at Highburywhich Arsenal won, although Quincy missed his kick. He scored his first goal for the first team in the same competition on 9 November 2004 against Everton, a match in which he also made two assists, and contributed two appearances to Arsenal's victorious 2004–05 FA Cup campaign. He produced an impressive performance against Reading during the Gunners' 2005–06 League Cup run.