The seventh seeds claimed their ninth straight victory to claim the trophy after 70 minutes, they saved all four break points they faced.
Mahut and Herbert have claimed all 18 sets they have contested since the Paris Masters which they won last month and they are the first winners.
The career Grand Slam winners are the first team to lift the trophy at the O2 without dropping a set since Jean-Julien Rojer and Horia Tecau in 2015.
They are now at 19-5 this season and as a result, they will claim 1,500 ranking points with $533,000 in prize money.
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