The 65-year-old coach says he wants his players to give their all as they look to clinch continental glory against Atletico Mineiro in the second leg
The Paraguayan side hold a definite advantage heading into the away fixture, with a 2-0 lead from the first leg last week.
Almeida, who was part of the Copa Libertadores-winning Olimpia sides in 1979 and 1990, does not want to see a half-hearted performance from his side and insists that triumphing this year will not be a miracle but down to hard work and belief.
"I will probably tell my players that I don’t want to see a single clean shirt in the dressing room afterwards, but rather dirty, stained and sweat-soaked ones – torn and in shreds if that’s what it takes," the 65-year-old told Fifa.com.
"It’s true, few people thought we could even get past the first round. The squad was practically the same group of players who had finished our league championship with a rout at the hands of a team that nearly went down.
"People ask me now if what we’ve done is a miracle, and I tell them no - it’s the fruit of hard work by a group that became convinced of what they could achieve if they united behind an idea.
"No-one gave us much of a chance in 1979 either, and nor was our football at a great level. It was like this season: a coach came along who got us playing a certain way and made us believe."
The clash between the Paraguayan side and the Brazilian club kicks off at 02:50CET on Thursday or 21:50 local time on Wednesday in Belo Horizonte.