For much of this game there was little to separate the two sides.
Sunderland struggled to play with tempo and Shrewsbury were intelligent and diligent, belying their poor start to the season.
It bodes well for the Black Cats, then, that they were able to turn the tide from the bench and grind out a vital win.
Jack Ross was decisive in his subsitutions, an outstanding cameo from Lynden Gooch turning the tide and breaking the host's spirits.
To add to the delight, Luke O'Nien added a second within minutes of entering the field.
It was a battling win but one that extends Sunderland's good run of form in recent weeks.
Ross had hoped that the international break and growing continuity in his selection would help the Black Cats begin to build real momentum in the League One campaign.
It had looked that way in the early stages, the visitors on top and forcing a number of promising set pieces.
They came to nothing, and gradually a sloppiness began to slip into their play.
Shrewsbury ought to have taken the lead when Omar Beckles headed a cross over the bar, the hosts pressing high and preventing Sunderland from building any pressure on the ball.
They were their own worst enemies in that regard, giving it away on countless occasions.
Lee Cattermole, booked in the early stages for a rash challenge, did come close to a goal when he made an excellent late run into the box. Jerome Sinclair's cross was precise but on his weaker foot, the midfielder could only fire over.
Sinclair was Sunderland's one real threat in a poor opening half, causing problems when he drifted into the channels. Had Josh Maja been able to control a similar cross minutes later, the Black Cats would have been ahead.
Shrewsbury should have opened the scoring ten minutes before the break. A Shaun Walley free-kick from wide on the left drifted onto the woodwork, Jon McLaughlin beaten. The onrushing defender looked certain to convert but blazed over, the linesman's flag also raised.
Unimpressed by how his side began the second half, Lynden Gooch and George Honeyman were quickly introduced from the bench.
The reward was immediate. Gooch played a quick one-two with Dylan McGeouch, before crossing the ball into a dangerous area. With Tom Flanagan looming over his shoulder, Beckles tried to clear and could only slice into his own net.
Sunderland began to up the tempo and Joel Coleman had to be alert to turn an effort from Chris Maguire away from goal.
Gooch nearly got on the scoresheet himself 20 minutes from the end, just unable to turn an excellent cross from Reece James towards goal.
Shrewsbury did show a response to falling behind, and the Black Cats were fortunate that substitute Aaron Amadi-Holloway could only head wide from a deep cross. McLaughlin had looked in little danger initially but ended up scrambling for his back post. The forward has another good chance soon after, finding space in the box but making a mess of his half-volley on goal.
Ross made his third sub, and the results again were immediate.
Luke O'Nien has not had an easy start to his Sunderland career but replacing Jerome Sinclair, he showed his key attributes with an excellent goal.
A good supporting run offered the chance to break into the box. O'Nien won a 50-50 challenge, the ball breaking for Gooch. His pass was precise, O'Nien gathering and scoring an emphatic half volley.
Defeats for both Peterborough United and Barnsley only served to underline the importance of these three points.
Sunderland XI: McLaughlin; Matthews, Flanagan, Baldwin, James; McGeouch, Cattermole; McGeady (Honeyman, 57), Maja (Gooch, 54), Maguire; Sinclair (O'Nien, 82)
Subs: Ruiter, Ozturk, Mumba, Kimpioka
Shrewsbury XI: Coleman; Emmanuel, Waterfall, Sadler, Beckles; Laurent (Amadi-Holloway, 69) , Grant, Docherty; Gilliead (Haynes, 69), Angol, Whalley (Norburn, 77)
Subs: Arnold, Okenabirhie, Bolton, Barnett
Bookings: Cattermole, 13
Attendance: 9,007 (1,640 away)