Pearson put Burton in front from the penalty spot in the 31st minute and Maghoma struck 11 minutes from the end to clinch the home side's first win in five games.
A nervous Burton defence might have been punished in the opening stages but goalkeeper Adam Legzdins kept out a Brian Smikle shot and spared team-mate Darren Moore an own goal with one-handed saves.
Albion recovered and their persistent pressure was rewarded in the 31st minute.
Pearson netted from 15 yards after riding Gallinagh's challenge but referee David Foster had already whistled for a penalty - and the full-back was sent off before the Burton striker converted the spot-kick.
Smikle had a goal disallowed for the visitors in the 78th minute before Burton broke to allow Maghoma to seal victory with a close-range finish.
Source: PA
Source: PA