Atletico won the Spanish league title for the first time in 18 years last term and were losing finalists to Real in the Champions League before top scorer Diego Costa and fullback Filipe Luis departed for Chelsea along with on-loan goalkeeper Thibaut Courtois.
Players Atletico brought in included Croatia striker Mario Mandzukic, France forward Antoine Griezmann and Italy winger Alessio Cerci, and Simeone said their integration was ongoing as they prepare to play at Greek champions Olympiakos Piraeus on Tuesday in the latest edition of Europe’s elite club competition.
“We are a work in progress after the arrival of the new players,” Simeone told a news conference in Athens ahead of the Group A opener.
“We will try to create a cohesive group without changing our style,” added the Argentine, who has transformed Atletico into genuine contenders in Spain and Europe since taking over at the end of 2011.
Atletico and Olympiakos have met just once in European competition, when the Spanish side won 4-2 on aggregate in the quarter-finals of the European Cup Winners’ Cup in 1992-93.
The Greeks made it to the last 16 of the Champions League last term and beat Manchester United 2-0 at home before losing 3-0 in the return.
The club’s Spanish coach, Michel, who played for Real and Spain, said Atletico’s win at their crosstown rivals at the weekend was evidence that Simeone still had a formidable team despite losing some key performers.
“Atletico has changed some players but they are still as strong as ever,” Michel told an earlier news conference.
“They are a team that has been put together with a lot of hard work so changes in individuals does not mean that much.
“Simeone has created a genuine unit and the results speak for themselves.
“But we are completely prepared. We have the experience and we will fight hard to get a result.”
(Writing by Iain Rogers, editing by Stephen Wood)