 In the summer 2002 Olympiacos made a 2 years contract to Katergiannakis as second goalkeeper behind Dimitrios Eleftheropoulos.Katergiannakis won the Greek Super League with Olympiacos in the season 2002/2003, after a big competition with the other goalkeeper Dimitrios Eleftheropoulos that he become injured during the match with the rival Panathinaikos.Katergiannakis became the first goalkeeper helping his new team to win the 7th consecutive Greek League and qualifying the team for Champions League and reached the final of Greek Cup against the Greek rival AEK Athens.