Atletico boss Diego Simeone says his team are still a work in progress – despite their impressive Madrid derby exploits.
Los Rojiblancos begin their Champions League campaign in Greece just days after humbling neighbours Real at the Bernabeu.
That result was all the more impressive when you consider the high turnover of players the Spanish champions endured over the summer.
Simeone said: “We have to forget about this win [over Real]. Yes, it was an important result for the team and for our fans. We had never in the club’s history beaten Real Madrid twice in a row in the league. But we cannot forget that we are starting over. We had 10 players leave this summer and we need to work hard to grow and improve.
“We are getting better and improving some aspects without compromising our style.”
Olympiakos boss Michel is well known to Simeone after his stints in charge of Sevilla and Getafe.
And the Spaniard has played down the Greek title holders’ chances of making it out of a group which also includes Juventus and Malmo.
“Atletico and Juve are very tough opponents,” he said.
“These two teams are the favourites to go through and do well. My hope is that my players can hand good performances in every game.
“As always, we will do our best to reach the next round.”