Four players were given 90 minutes of action for the first time in the pre-season but chances proved hard to create against the Serie A side who won it with a second-half strike.
A crowd of 57,748, the second highest for a football match in this stadium in Miami, saw the Blues the better side early on but we did not improve on an early John Terry shot as the best attempt on the Milan goal.
From midway through the opening period it was an even contest which was decided when Chelsea were caught by a piece of swift counter-attacking play. Fitness is coming on but there is still work to do on the training pitch before the season begins.
Raul Meireles was handed his first start of pre-season and played as the central midfielder behind Romelu Lukaku who began for the fourth match in row on this tour. The defence and two deeper midfielders were the first-choice selection at the end of the last campaign.
Eden Hazard played on the left with Ramires on the right.
Milan left Antonio Cassano on the bench and were without Robinho so started Kevin-Prince Boateng as centre-forward.
Ashley Cole had to flick away a cross from left-back Mesbah that had cleared Petr Cech in the opening minutes, but the first chance was Chelsea's, Ivanovic heading a free-kick across the area for a falling Terry to half-volley over. It was difficult opportunity.
Hazard was looking bright when on the ball early on but although Chelsea enjoyed the bulk of possession, the next chance was a long while in coming.
There was a moment of concern at the back when Traore nipped onto a loose ball but his hopes of a free-kick as it escaped his control and he tumbled were dashed. The ref decided there had been no contact with close-by John Terry.
The same Milan midfielder shot wide soon after and Ivanovic did well to hold off Flamini inside the Chelsea area as the Blues had to do some defending around the half-hour mark.
The Italian side were improving after a start when Chelsea looked much sharper and we were exposed down the middle by a swift break in which Boateng did well to keep the ball under control. He slipped a pass out to Emanuelson who should have got his shot on target.
Chelsea were finding it difficult to work the ball to players in threatening areas but there was still the possibility of some set-piece joy. The combination that had opened the scoring in the previous match, against the MLS All-Stars, attempted to do the same again, Terry meeting a Lampard corner but this time he headed wide and was annoyed by a shove from a marker.
Marko Marin replacing Meireles was the only change by either side at the interval. Hazard moved into the centre and almost instantly won a free-kick with an incisive run. From 25 yards out Lampard drove it into the wall. The pressure remained on Milan until Mikel fired a shot into the grip of the keeper.
Lampard soon after sent over a corner that Amelia in the Milan goal misjudged badly but got away with it.
On 50 minutes Lampard was guilty of giving the ball away in his own half, allowing Emanuelson to attack Terry and slip a shot past but Cech dived low to punch away; the best effort and the best piece of goalkeeping in the game so far.
At the other end Lampard was found advancing by Lukaku but although his strike was crisp, it was straight at the keeper.
Ivanovic and Hazard then almost made something happen inside a crowded Milan area on 55 minutes. Chelsea were beginning to play a bit.
There were three changes just before the hour - Ferreira, Cahill and Torres on for Cole, Terry and Lukaku - with the Spaniard's introduction especially welcomed by the crowd in this Latin-flavoured part of the US.
However it was Milan who took the lead, punishing the Blues by nicking possession just inside their half and attacking swiftly. El Shaarawy looked certain to score but the ball deflected off Cech, only for Emanuelson to sweep it in. There were 68 minutes played.
Cech slipped when trying to deal with an attempt to beat him from inside Milan's half but was saved embarrassment as it travelled on wide of the target.
Time was running out. Hazard continued to look the most likely to unlock Milan's defence, just crowded out while making one exciting run, but when he tried a free-kick after Torres had been shoved marginally outside the area, he curved it over the bar.
The final chance of the game fell to our opponents when Mikel headed loosely back but it was sent wide of Cech's goal.
The team fly directly back to the UK after the game, with match action resuming in a week's time in Brighton.
Chelsea (4-2-3-1): Petr Cech; Branislav Ivanovic (Sam Hutchinson 76), David Luiz, John Terry (c) (Gary Cahill 58) Ashley Cole (Paulo Ferreira 58); John Mikel Obi, Frank Lampard (Michael Essien 76); Ramires (Florent Malouda 76), Raul Meireles (Marko Marin h-t), Eden Hazard; Romelu Lukaku (Fernando Torres 58).
Unused subs Jamal Blackman, Nathaniel Chalobah, Lucas Piazon.
AC Milan (4-3-3): Marco Amelia; Luca Antonini (Ignazio Abate 61), Daniele Bonera, Mario Yepes (Francesco Acerbi 61), Djamel Mesbah; Bakaye Traore (Kevin Constant 79), Massimo Ambrosini (c) (Antonio Nocerino 61), Mathieu Flamini (Riccardo Montolvio 61); Urby Emanuelson (Simone Andrea Ganz 86), Kevin Prince-Boateng (Mattia Valoti 73), Stephen El Shaarawy.
Unused subs Mattia De Sciglio, Bryan Cristante, Edoardo Pazzagli, Philipp Prosenik, Antonio Cassano.
Goal Urby Emanuelson 68.
Referee Ricardo Salazar