Gomez and Jones feature in Sunderland win
Gus Poyet's side were given a good pre-season test by the League Two side, but the manager will have been concerned to see defender Modibo Diakite limp off in the first half at Brunton Park.
Mikael Mandron, who spent part of last season on loan at Fleetwood Town, scored the decisive goal 19 minutes from time.
It was the hosts who came closest to breaking the deadlock before the break, David Amoo's goal-bound shot being blocked by Wes Brown in the 35th minute.
Jones spurned a presentable opening on the stroke of half-time when the former West Brom full-back failed to generate enough power on his effort, allowing Danny Grainger to clear the danger.
The visitors made several changes in the second half, with the largely ineffectual Gomez among those to make way, and Mandron's excellent finish from inside the box eventually gave them the victory.