The hosts were cruising after Ervin Zukanovic volleyed the Flying Donkeys in front, a lead unthreatened until Allesandro Matri levelled for Genoa- sparking a collapse as Ivan Radovanovic was sent off and Mauricio Pinilla scored the winner.
“We gave an hour of good play, and should have closed the game out,” the 51-year-old told Radio Rai.
“Then immediately after the goal and the red card we lost the plot.”
Radovanonic’s red card, given for a second yellow as the Serb fouled Andrea Bertolacci in the area, led to Pinilla missing a penalty.
However, the visitors recovered to seal the win as Pinilla scored at the far-post with seven minutes left.
“It is too bad; we have to bring home important points.
“The team played well for an hour, if we repeat that I will be happy- it is an undeserved defeat.”
The Rossoblu now travel to Palermo for a crucial game on Wednesday, with Palermo sitting 18th in Serie A, and Maran’s Chievo 19th.