At half-time, Nathanael Ogbeta was taken off.
The youngster may well have been injured but either way, it was a call you weren’t surprised to see Manchester City boss Paul Harsley make.
Ogbeta was on a yellow and had endured a torrid 45 minutes.
Every time he turned, there was Duncan Watmore, bearing down on his shoulder and sending him backwards.
Watmore played just an hour but wasted barely a second.
His goal capped his best display since returning from injury.
Jack Ross has managed that return perfectly.
Last season as Sunderland stumbled through the early stages of the campaign, Watmore became a player it felt like the Black Cats couldn’t be without.
That brought real pressure but this time around it has seemed far more low-key.
Only on Saturday, Ross said again that anything he ekes out of him this season is a bonus.
So far, his cameos have shown fleeting promise but no end product.
That was highlighted perfectly against Scunthorpe United when the 24-year-old broke through on a couple of occasions but just couldn’t find the crucial touch.
It has, understandably, been that way for much of his ten appearances this season.
He has been a good outlet on the break but a player still searching for confidence.
In order to protect his body Ross has used him as a central striker, allowing him to avoid the lung-busting runs back towards his own goal that come from playing on the wing.
It is off the right that he looks most comfortable nevertheless and in that position he was simply excellent against Manchester City U21s.
His goal was superbly taken, rifling home a loose ball in the box.
A couple of superb defensive runs early in the second half, shortly before his departure on the hour mark, underlined an impressive all-round contribution.
Ross will remain calm about Watmore, but his performance came as a major boost at a time when the Black Cats boss is searching for freshness and a spark after a difficult run.
The important of extra competition was seen when Lynden Gooch, was has been off the boil recently, replaced Watmore and promptly scored an excellent goal.
It has been a testing spell for Sunderland but this comfortable win provided welcome relief.
Ethan Robson returned to action and looked in good order.
Adam Matthews returned for injury and Luke O’Nien revelled in his return to an attacking midfield role.
Thriving at right back has done wonders for his confidence and he again showed signs of his threat when shooting from range and making late runs into the box.
Ross knows he has a pivotal ten days before AFC Wimbledon arrive at the Stadium of Light.
He needs a boost in the transfer market and to ensure that the Josh Maja saga is brought to a satisfactory resolution.
Despite this good performance, he will also know that he has work to do to get his formula right for what will be a testing conclusion to the League One season. There is much work to be done for the Black Cats to get over the line.
Yet in the bigger picture they are third in the table with a game in hand on those above them.
And now, they are just one win away from a cup final at the national stadium.
He has challenged his players to come back refreshed, energised and ready to achieve something special.
What a wonderful story it would be if Duncan Watmore, who has endured such a difficult two years, could play a part in doing exactly that.