Simeone said: "We knew that we'd be facing an intense Milan, especially in the first half. We started well, then started losing the ball too often and suffered down the right flank.
"We weren't fast enough and struggled to come out, so that helped Milan. We changed after the break, Mario got well between the central midfielders and we slowly started to gain more possession, to move up the field and play the game we wanted.
"Everyone knows when you reach the knockouts any mistake can get you eliminated. Courtois performed a great save on Poli, but in the second half we played intelligently in tactical terms and slowly gained our chance to win the game."
Simeone explained the tactical shift during his half-time team talk that made the difference.
"In the first half we started with four in midfield and thought we could do a lot better down the right, but it didn't go as planned. We weren't starting well with Juanfran either, but when we put five in midfield we had an extra man and made the most of it.
"We are aware of what we've got and what we don't. That is the strength of this team over the last two years, as we know our limitations and build on what we can do."
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