The Polish keeper flapped Danny Green's cross into his own net for the only goal of the game as Charlton overcame stubborn resistance from an Exeter side that defended well, but created little in attack.
The first half was devoid of any decent chances, but it was Exeter that looked the more threatening. John O'Flynn, James Dunne and Jake Taylor should all have done better with half chances, but failed to test Charlton goalkeeper Ben Hamer.
Charlton's best opportunity came early on when former Exeter captain Matt Taylor hooked a volley goalwards, but it was hacked off the goalline by Richard Duffy.
The deadlock was eventually broken 10 minutes into the second half in fortuitous circumstances. There seemed little danger when Green crossed from wide on the right, but Krysiak, under no pressure, misjudged the flight of the ball and palmed it into his own goal.
Exeter huffed and puffed as the game wore on, but Guillem Bauza's shot, which was saved by Hamer, was as close as they got as the Addicks' defence held firm.