Two deafening roars, one quickly followed by another.
First Luke O’Nien, increasingly influential as a supersub, won a challenge and headed for the corner. A foul from a frustrated opponent followed, and the 4,000 in the away end exploded.
Then came the final whistle, greeted with an outpouring of relief and ecstasy.
Dylan McGeouch led the celebrations, stoking the passion of those who turned the Keepmoat Stadium into what felt like a home arena for the Black Cats.
The chanting was relentless for long afterwards.
‘We’re on our way’, the staple song of promotion pushes from yesteryear, sung with gusto.
After three away wins on the bounce, it is starting to feel apt.
Why did this win feel so good?
Not because it had been an exhibition of attacking football, a show of prowess and individual skill.
It felt so good because it had been so hard fought.
Sunderland have arguably not faced a better opponent than Doncaster Rovers.
Grant McCann’s side have won praise for their quality on the ball and their intensity off it.
Both were on show, particularly in a first half when Jack Ross’s side were unquestionably second best. The hosts were quicker to the ball in midfield and in possession they were able to move it swiftly through the lines.
That Sunderland’s midfield were all on yellow cards before the half was out told its own story.
The Black Cats unquestionably had their moments, Jerome Sinclair battling hard and creating some openings when he fought his way into the channel.
Doncaster would have been worthy of the lead nevertheless, and only the brilliance of Jon McLaughlin prevented them taking it.
Two outstanding saves helped keep the scores level and Chris Maguire capitalised soon after.
McLaughlin has quickly established himself as arguably the most consistent, impressive player in the squad.
It is no great stretch to say that he could have kept Sunderland in the Championship last season. He is making vital stops week in, week out and his quality gives the Black Cats a significant advantage in the push for promotion.
Bringing him in on a free is already one of Jack Ross’s best moves since taking charge.
Doncaster continued to threaten as the game developed but as they had done with ten men a fortnight or so ago, the visitors managed a difficult period impressively well.
Ross again was able to bring some energetic players on from the bench, carrying the ball away from danger and relieving the pressure.
At the heart of defence, Tom Flanagan and Jack Baldwin delivered another display that matched quality with real tenacity.
The away support, with Chairman Stewart Donald in their ranks, responded to a performance that did not showcase the best of Sunderland’s quality, but did highlight the impressive unity they have built in a short space of time.
Ten games into the season Jack Ross had admitted his frustration with certain results, but highlighted how good the mood was behind the scenes.
He felt certain that at some stage it would begin to deliver consistent results.
That is beginning to hold true, and the togetherness has been apparent in the way Sunderland have closed out these last three games.
It has given the Sunderland support a team they’re proud of.
They will see better performances this year, but they may not see many more significant ones.
Their joy on the final whistle underlined that. Not for the first time, it wasn't plain sailing.
But Sunderland are very much on their way.