Jonson Clarke-Harris struck his 31st goal of the season early in the game before Josef Bursik saved a penalty just after the half hour mark.
Posh defended superbly as Charlton failed to create any clearcut opportunities in the second half..
RATINGS KEY: 10-Brilliant, 9-Outstanding, 8-Very Good, 7-Good, 6-Okay, 5-Poor, 4-Dreadful.
5.
MARK BEEVERS: Massive performance from the skipper against Jayden Stockley. He was battered and bruised at times, but he kept coming back for more 8.
6.
ETHAN HAMILTON: A strong shift from the midfielder who ran hard throughout his 70 minutes on the pitch 7.
7.
JACK TAYLOR: He was far from his best with his passing, but he battled gamely throughout. Helped protect the back four in the second-half 6.5.
8.
JOE WARD: Started the game impressively and he was still running hard and pressing at the end. Excellent quality at times and very good work ethic throughout 8.