Olympiakos narrowly escaped what would have been a major upset in the fourth round of the Greek Cup last night by staging a late comeback to defeat third-division host Diagoras 2-1 on the island of Rhodes. Last night’s knockout tie was the Greek Cup’s remaining encounter before the Round of 16. Preoccupied by next week’s concluding group game in the Champions League against Werder Bremen – a draw or better will get Olympiakos through to the prestigious competition’s next stage, the Round of 16 – coach Takis Lemonis fielded mostly substitutes for last night’s encounter, played on a muddy pitch and under heavy rain. Two regular starters, Predrag Djordjevic and Luciano Galletti, who were both expected to spend the rainy evening resting on the bench and under its shelter, needed to join the action late in the game to help their less experienced teammates rebound from an ominous looking 1-0 deficit. Diagoras took the lead on the hour from the penalty spot after Tassos Triantafyllou converted successfully. Earlier in the game, Olympiakos striker Michalis Constantinou, a second-choice starter for Lemonis since the summertime arrivals of Tresor Lua-Lua and Darko Kovacevic, squandered a penalty kick in the 35th minute of play. Another pre-season signing for Olympiakos, young striker Costas Mitroglou, became the evening’s hero, scoring both goals for his club. The 19-year-old, who transferred to Olympiakos from German club Borussia Monchen-gladbach, equalized in the 66th minute and, with one minute left on the clock, beat the Rhodes team’s keeper in the air to make it 2-1 for the Piraeus visitors. Olympiakos has never been eliminated from the Greek Cup by third-division competition. Last year, the Super League powerhouse was knocked out of the competition by a second-division club, PAS Yiannina, for the first time in the club’s history. Later last night, Panathinaikos, already through to the UEFA Cup’s next round of 32, was at home against Lokomotiv Moscow in Group B. AEK was hosted by Mlada Boleslav, needing points to bolster its place in Group C. Tonight, Thessaloniki club Aris is at home to Portuguese team Braga looking for a win in Group F of the UEFA Cup and a berth in the competition’s Round of 32. Panionios is hosted by Austria Wien needing victory to improve its hopes of continuing in the next round.