The Greek outfit beat Manchester United in the Champions League on Tuesday and the Argentine believe his side's achievements will long be remembered
The Greek champions claimed a 2-0 win over Manchester United in the first leg of their last-16 clash on Tuesday and stand on the brink of the quarter-finals.
And though the Argentine is adamant that the tie is far from over, he says his side are confident of making a splash in the competition.
"I am so happy. I am very satisfied with the team's work and the victory we achieved. I believe we have made a big step – a giant leap forward," he told Uefa's official site.
"The tie is not over yet. We have the away leg to play, but we should enjoy today's result. For me, this is a historic night for the club and we are thrilled about it.
"The coaching staff prepared the match in detail and today everything went exactly as we had planned. We were at our absolute best.
"With everything going perfectly for us, we had a great match and made a big step towards qualification.
"Manchester United are not easy opponents. They know this competition and have to be respected.
"However, we have our weapons on the pitch – we gave it everything we've got and achieved a great result which is very important for us."