Charlton had to leave it late to overcome a brave rear-guard action by 10-man Peterborough with a 2-1 win.
An 88th-minute goal by Macaulay Gillesphey undid the visitors, who saw Emmanuel Fernandez dismissed.
A shot from outside the area by Luke Berry hit the post after 32 minutes, before Jed Steer had to save from Matty Godden at point blank range a minute later.
The game kicked into life in an amazing eight-minute spell. After increased Charlton pressure, the visitors were undone by a penalty after 54 minutes. Sam Hughes handled in the box, with Godden converting from the spot.
It looked to become an awful evening for Peterborough when Fernandez was dismissed after 58 minutes for fouling Thierry Small.
However, they hit back three minutes later from a Malik Mothersille spot kick, after Ricky-Jade Jones was upended in the area.
The Peterborough resolve was finally broken when Gillesphey headed home an 88th-minute corner to scupper their chances of a valuable point.
Subscribe or register today to discover more from DonegalLive.ie
Buy the e-paper of the Donegal Democrat, Donegal People's Press, Donegal Post and Inish Times here for instant access to Donegal's premier news titles.
Keep up with the latest news from Donegal with our daily newsletter featuring the most important stories of the day delivered to your inbox every evening at 5pm.