Julio Arca's strike took Sunderland into the fourth round of the FA Cup.
The Argentine netted in the second-half, latching on to a long clearance which Pools' defence could not handle.
The goal was harsh on the visitors who often threatened, particularly through Eifion Williams and Paul Robinson.
Arca and strike partner Marcus Stewart both struck the post for Sunderland in the first-half, but Hartlepool looked more likely to score late on.
Stewart's left-foot effort against the woodwork was the first real chance of the game after just eight minutes.
But despite that bright start, it was the visitors who began to take control.
8 mins: Stewart hits post for Sunderland
38 mins: Arca also fires against the woodwork for Black Cats
53 mins: Arca puts the home side ahead against run of play
Sunderland keeper Mart Poom had to be alert to save a Robinson shot on 13 minutes, and the Black Cats were even more grateful to the Estonian just after the half-hour.
He saved comfortably from a Robinson right-footer on 33 minutes, and one minute later produced a superb effort to tip over a curling shot from Williams.
For Sunderland, Jon Oster and Jeff Whitley both squandered chances.
The home team almost took the lead just before half-time, as Arca's long-range shot struck the same post as Stewart's earlier effort.
Poom was again in action in the first minute of the second half, tipping over a powerful right-footed drive from Williams.
Yet it was Sunderland who took the lead, somewhat against the run of play on 53 minutes.
Arca was the scorer, latching on to a long clearance which eluded Michael Nelson and Chris Westwood, to fire a low left-footed shot past Jim Provett.
The goal lifted Sunderland, and Provett produced a great reaction save from a Stewart header after Arca's cross.
But Pools came back again, with the ever-lively Williams cursing his luck was unlucky when his close-range left-foot volley was blocked by Stephen Wright.
Richie Humphries also came close, drilling over from the edge of the box and Stephen Istead saw a close-range volley blocked by Phil Babb.
Nelson and Williams again both saw shots blocked for Hartlepool in a frantic finale, but Sunderland held on.
Sunderland: Poom, McCartney, Babb, Bjorklund (Williams 74),
Wright, Oster (Butler 83), Arca, Whitley, Clark, Proctor,
Subs Not Used: Ingham, Ramsden, Teggart.
Hartlepool: Provett, Barron, Nelson, Westwood, Robson,
Shuker (Istead 64), Tinkler (Clarke 80), Strachan, Humphreys,
Williams, Robinson (Porter 71).
Subs Not Used: Konstantopoulos, Brackstone.
Referee: G Barber (Hertfordshire).