Stewart would score again either side of striker from Elliot Embleton, Nathan Broadhead and Danny Batth as Alex Neil’s side extended their unbeaten run to eleven games.
Though there remains much work to be done Sunderland will go into the final two games of the season with their fate firmly in their own hands.
The game had swung on the red card, though it was also fair reward for a Sunderland side who pressed with aggression from the off and caused problems when they exposed the visitor’s high line
There was no doubt that Jones had bundled Stewart over inside the box after the Scot shielded a loose ball superbly, but the red looked harsh given a seemingly genuine attempt to get to the ball. No matter for Sunderland, as Stewart stepped up to send Mitov the wrong way.
It was far from the perfect start all the same, Sunderland suffering a major blow when Winchester left the field in obvious discomfort following a muscle injury.
His side were dominating ten-man Cambridge, Roberts firing straight at Mitov after a clever run inside the box. Embleton then curled an effort just wide after breaking into the box, but found that far corner minutes later with an audacious free kick from a narrow angle by the byline.
Neil was left irate when his side allowed Cambridge to reduce the deficit within a minute, Digby firing home from close range after a good run by Willians down the right flank. But Sunderland’s response was excellent, Stewart gathering a low cross from Gooch and volleying into the far corner with ten minutes to play before the break.
Gooch was excelling, good crosses almost yielded a third when Broadhead and then Stewart headed just wide.
The visitors were hanging on, Broadhead’s header saved superbly by Mitov before Roberts had an effort blocked at close range.
Sunderland stepped up the intensity again after the interval and were rewarded within ten minutes, another inch-perfect delivery from Gooch headed calmly into the far corner by Broadhead. At this stage it looked like a question of how many for the hosts, Cambridge unable to get out of their own half. They did go close when a long throw dropped for Okedina on the edge of the six-yard box, but his volley was well over the bar.
Sunderland continued to dominate, substitute Alex Pritchard heading a Gooch cross inches wide of the far post.
The fifth came shortly afterwards, a short corner worked to Roberts whose cross to the back post was headed home emphatically by the stooping Danny Batth.
The closing stages were dominated by the hosts as Cambridge looked to limit the damage. The intensity dropped somewhat as greater challenges came onto the horizon for Neil’s side, but they continued to threaten and could have added a sixth as Stewart and O’Nien both went close with headers from inside the box.