Both sides named strong starting XIs with Chelsea starting arguably its best back line, while the likes of Eden Hazard, Raul Meireles and Frank Lampard roamed further forward.
Milan, where the squad is looking massively depleted following a summer of upheaval, included the likes of Kevin-Prince Boateng, Massimo Ambrosini and new signing Boakye Traore from the start, while Antonio Cassano and Riccardo Montolivo took places on the bench.
The first half saw very few clear-cut chances, with John Terry probably having the best two openings, smashing the first effort over before heading wide late on.
In terms of big chances the second half wasn't much of an improvement, but a goal was eventually scored with just over 20 minutes to go as the impressive Urby Emanuelson found the net after Petr Cech could only partially stop Stephan El-Shaarawy's close-range strike.
The first chance of the match came at the end of a cleverly-worked free kick by Chelsea, with Hazard clipping his left-wing delivery to the far post where Branislav Ivanovic nodded down to Terry, but the Blues skipper put his half-volleyed effort just over the bar.
Moments later Hazard was causing trouble down the left once again, this time using his dribbling skills as he side-stepped Luca Antonini before skipping between the right back and Daniele Bonera, bursting in the penalty area, but his shot was blocked well by Mario Yepes.
With 20 minutes gone the Premier League side was generally controlling the tempo of the match while also restricting Milan to very little possession in the attacking third and the club still had not managed a single shot.
Milan, which has only played one preseason match so far, had its first effort after 27 minutes. El-Shaarawy did well on the right before passing short to Traore, but the Senegalese midfielder’s toe-poked effort was poor and went comfortably wide.
The Italian almost had another chance a minute later as Urby Emanuelson twisted his way past a couple of defenders before feeding Mathieu Flamini into the left side of the penalty area, but Ivanovic did well to shepherd the ball back to Petr Cech.
Massimiliano Allegri’s side continued its resurgence and this time Emanuelson was the one in the penalty area, but after Boateng’s well-weighted pass the Netherlands international side-footed his effort over the bar from a good position, much to the despair of the former Portsmouth star.
Emanuelson was getting himself involved everywhere in attack as the first half rolled on and El-Shaarawy was the next to link up with the Dutch midfielder, who cut inside from the right before finding the Italian forward who shot right footed, but once again it was easy for Cech.
After a quiet period Chelsea went close with four minutes left of the first half as Terry headed Frank Lampard’s corner just wide meaning the two teams went into the break level at 0-0 following a drab first 45.
The second half started in a much quicker fashion with both teams attacking with intent, while the introduction of Marko Marin injected some added flair to the Chelsea attack and Hazard moved into a central role.
However, it was Milan which went closest in the opening minutes as the tricky Emanuelson marched into the penalty area, fooling Terry with a drop of the shoulder and then shooting with his left foot, but Cech was equal to the effort.
Within seconds Chelsea was back on the attack. Romelu Lukaku - who had been poor throughout the first half – cut the ball back to the edge of the area for Hazard, but the clever Belgian simply stepped over the pass, leaving it for Lampard. Marco Amelia got down to make the save from the midfielder’s strike.
The fast-paced action continued as both sides exchanged possession a great deal, but neither team was creating much with defense coming out on top continuously, until the 69th minute.
Boateng played an excellent pass in behind the Chelsea defense for Emanuelson to run on to, but instead of shooting he cut the ball inside to El-Shaarawy whose shot came back to the Dutch midfielder after a Cech save. There was no stopping the second effort as the Netherlands international opened the scoring from close range.
The goal instilled even more confidence into the Milan team which was knocking the ball around excellently after Emanuelson’s goal, while a raft of changes for Chelsea made the club look even more disjointed.
With 10 minutes left Roberto Di Matteo's side was attacking with more intent, but Hazard and Co. were finding it increasingly hard to break through the Milan defense, with Fernando Torres constantly dropping deep, while Marin was failing to impose himself.
Chelsea felt aggrieved in the final 10 minutes when the team thought it should have had a penalty for a a Bonera shoulder-barge on Torres, but only a free kick was given and Florent Malouda blasted it over.
The final minutes saw Milan passing the ball around, playing the clock down in disciplined fashion, a tactic that paid dividends as the club held on for the narrow win.
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