Champions Manchester United, who failed to win their opening three games, won 1-0 for the second successive week to continue their climb up the table.
They welcomed old midfield warhorse Roy Keane back to Old Trafford for the first time as Sunderland manager and then had to work hard to beat his resilient side.
The breakthrough came after 71 minutes when Louis Saha, on as a halftime substitute to end a six-month injury layoff, headed home from a corner taken by Nani.