The Blues scored first courtesy of former Atletico man Fernando Torres to inch closer to a berth in the Lisbon final, but Atletico equalised via Adrian before half-time - and added another two goals via Diego Costa and Arda Turan to cruise to a 3-1 second-leg, and aggregate, victory.
"They had the first chance of scoring and, luckily, we could equalise quickly," Simeone said.
"That created, in the second half, the possibility of playing the match that suited us best.
"After the second goal, and when we played with five in the midfield, the possession and the game began to be ours.
"It's been a very important match."
Chelsea had been criticised for defensive, ugly tactics in their positive results in the first leg - a 0-0 draw in Madrid - and their 2-0 Premier League win over Liverpool.
But Simeone was not worried about Jose Mourinho's men, and hailed his side for their aggressive mindset that saw them pile on three goals when only one was needed.
"(I'm) happy because we played a good match," the Argentine said.
"We had to work hard to find the match we wanted and that was after the second goal.
"The consequence was a big collective effort and having everyone chasing after the same objective which is the team play that created the possibility of reaching such a lovely final."
Striker Adrian scored from a defence-splitting cross from Juanfran to put Atletico ahead on away goals, and Simeone praised his front man for coolly converting late in the first half.
"He's a player I dearly love and know he has the conditions to do well wherever he plays," Simeone said.
"I'm very happy for him. He hasn't had an easy year, but I never stopped trusting him. It can be seen in the chances to play I've given him.
"And what better way of repaying (me), than by putting back on track the match that got us in the final."
