Locker, selected in the first round of last year's draft, was named this week as Tennessee's starting quarterback over veteran Matt Hasselbeck. Locker completed 9-of-16 passes during a half of action, but the Titans trailed at the break 6-3.
Jamie Harper scored the game's only touchdown on a 1-yard run midway through the third period to give the Titans the lead.
Sean Canfield, listed as the No. 3 quarterback on the New Orleans roster, went the distance and completed 31-of-45 passes for 288 yards. He could not get the Saints in the end zone, however, and threw two interceptions.
Tennessee (3-1) will begin the regular season at home against defending AFC champion New England. The Saints (2-3) are scheduled to open in their hurricane-stricken home town against Washington.