Despite the 3-0 home victory, the Gunners fell to Milan 4-3 on aggregate after losing 4-0 at Giuseppe Meazza Stadium on Feb. 15 in the first leg.
Arsenal had the three-goal advantage after 45 minutes, as the Gunners played with urgency and efficiency. Defender Laurent Koscielny scored a header goal off a cornerkick from Alex Oxlade-Chamberlain in the seventh minute to put Arsene Wenger's squad ahead.
In the 26th minute, winger Theo Walcott found Thomas Rosicky who buried it in the bottom corner of net. Robin van Persie followed that up with a penalty strike in the 43rd minute.
Milan settled down in the second half, and had quality opportunities to score. Wojciech Szczesny was excellent in the net and kept a clean sheet despite some solid Milan chances.
Arsenal had a great opportunity near the one-hour mark. Gervinho delivered a shot in the box that was deflected, and Christian Abbiati made a fantastic save. Van Persie was there for the follow but Abbiati got his arm up to block the chip shot from close range.
Arsenal took nine shots, with seven on goal, while AC Milan recorded 13 shots, with five on goal. Milan edged Arsenal in possession by holding onto the ball for 55 percent of the match.
Here are the highlights from the Arsenal - AC Milan match: