Striker Griffiths produced a clinical finish before Patterson converted from a tight angle on the right inside 26 minutes as we made the most of the chances that came our way at Staplewood.
Goalkeeper and skipper Brandon Austin, the elder statesman of the group, produced a couple of smart stops as the home side looked to bring their fast-moving attackers into the game, but the unfamiliar central defensive pairing of Tariq Hinds and debutant Max Statham did well to keep them largely at bay.
The powerful Jonathan Afolabi rattled the crossbar twice from range as Southampton started to come into the game after the break, with substitute Kornelius Hansen pulling one back 11 minutes from time.