Arsenal became the first English side to defeat Milan on home soil thanks to late goals from Cesc Fabregas and Emmanuel Adebayor.
Defending champions suffer knockout blow on home soil
Arsenal scored two late goals to become the first English side to beat Milan on home soil and knock the UEFA Champions League holders out of this season's competition.
Cesc Fabregas and Emmanuel Adebayor struck in the final six minutes to seal a glorious European night for The Gunners.
Crisis, what crisis? Arsene Wenger's side came into the game without a win in their last four outings and having failed to grab a lead from the home leg.
However, they turned in a masterful display in Milan, dominating the match to prove youthful exuberance can overcome experience.
Fabregas, who had hit the bar in the first half, eventually broke the deadlock with a 25-yard low drive before Adebayor tapped in Theo Walcott's cross to seal the result in injury time.
Electric atmosphere
The San Siro was packed to near capacity, at 81,879, and the atmosphere was electric as the match kicked off. Wenger had been keen to ensure the Italians did not look to slow the tempo.
Arsenal started brightly, closing down Milan well and denying them space in midfield. After seven minutes, Alex Hleb found himself in space at the edge of the penalty area - but crashed his drive well over.
However, it was the hosts who almost snatched an early lead, when a corner from the left was flicked on at the near post by Paolo Maldini - and it needed a goal-line clearance from Fabregas to keep the ball out.
After 13 minutes, Arsenal broke quickly as Adebayor latched onto a long pass from Fabregas. The Togo frontman held the ball up and laid it off to the advancing Abou Diaby, but his placed shot from 20 yards was just over the top-right angle.
Arsenal keeper Manuel Almunia got down well to smother a far-post volley from Filippo Inzaghi as play continued to move from end to end.
A sweeping run by Kaka saw Milan break down the left in the 18th minute. As the defence backed off, the Brazilian chipped the ball to the far post, where Alexandre Pato really should have done better than just a feeble shot straight at Almunia.
Milan continued to press, with Inzaghi heading wide from a corner and Kaka's low drive skimming just the wrong side of the near post.
Adebayor - who hit the woodwork in stoppage time during the first leg - came close to scoring again after 27 minutes. The big African cut inside from the right, and his 12-yard drive was tipped over by Milan keeper Zeljko Kalac.
Arsenal were now enjoying a good spell themselves and Hleb was incensed after he appeared to be caught by Alessandro Nesta on the edge of the Milan penalty area - but was harshly cautioned by Austrian referee Konrad Plautz for what he saw as a dive.
Adebayor stepped inside before rolling the ball back along the 18-yard line to Fabregas. The Spaniard set himself before rifling in a drive which beat Kalac, but crashed against the crossbar.
Arsenal did well to keep possession, which frustrated the home crowd heading into the break, and had another golden chance to net that crucial away goal after the restart.
Bright start
A cross from the left found its way through to Philippe Senderos at the back post - but the defender's effort was hit straight at Kalac.
After 50 minutes, Emmanuel Eboue was played in on the overlap down the right side of the Milan penalty area, but blasted his angled drive wide.
Almunia had to be alert to turn away a 25-yard free-kick from Andrea Pirlo at full stretch, as the ball looked to be sneaking into the bottom right corner.
The pace was relentless as the hour mark approached. There was a warning for the Gunners, though, when Kaka broke down the left and surged to the edge of the penalty area before drilling his shot just wide.
Wenger sent on Walcott, replacing Eboue, and the England Under 21 winger almost set up Adebayor - but his cutback from the goalline was cleared.
Pato flashed an angled drive just wide from the left side of the penalty area as the tie remained on a knife-edge heading into the final 10 minutes of normal time.
Then, out of nothing, Fabregas broke the deadlock with a superb solo goal. The Spain midfielder picked up the ball, sidestepped Gennaro Gattuso and drilled a 25-yard strike into the bottom right corner.
Adebayor scored a second in added time, following a fine run and low cross from Walcott along the goal-line, to cap a magnificent night for the Gunners.
