It took just one Dan Neil expletive to lose his team this derby. No doubt Sunderland fans will be cursing him for some time.

After the hosts had controlled the first-half against local rivals Middlesbrough, Neil senselessly swore at referee Jarred Gillett and received a second yellow card that led to his team’s complete collapse.

Given the midfielder had earlier been booked for a lunge on Josh Coburn, he should have kept his head down and mouth shut.

But what appeared to be sweary complaints to Gillett about a missed foul in first-half stoppage time proved his and his team’s downfall. Four letters leading to a four-goal thrashing.

Neil, 21, has supported Sunderland his whole life so this moment of stupidity will certainly sting. Replays showed him pleading with the referee not to brandish the second yellow when it dawned he was in trouble.

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The Stadium of Light crowd was stunned into silence, not quite understanding how the red card had occurred, before fiercely showing their displeasure to Gillett. ‘Four-nil to the referee,’ they sang.

The half-time whistle brought a bust-up as Dan Ballard and Coburn clashed but afterwards it was Middlesbrough who kept clear heads as Sunderland lost discipline.

Sunderland-born Sam Greenwood fired Boro ahead and it was game over when Matt Crooks slammed home two minutes later.

The impressive Isiah Jones added a third, Marcus Forss the fourth and Sunderland were left wondering how it all went so wrong, so fast.

As we enter the international fortnight, this defeat shouldn’t detract from a decent enough opening to the Championship season for Tony Mowbray’s side.

Though they needed a helping hand here, Middlesbrough look to have turned a corner following a poor start. Michael Carrick’s team have now won five on the bounce in all competitions.

It was Sunderland who opened with the greater spark, their high press seeking to disrupt Middlesbrough’s passing out from the back.

Abdoullah Ba carved out the game’s first chance, driving in from the left and beating Boro keeper Seny Dieng with his curling effort only to clear the crossbar.

Mowbray had clearly figured out Boro’s defenders are vulnerable when you run directly at them and so Ba, Patrick Roberts and others were given licence.

Roberts was giving Lukas Engel a tough time and he dribbled from his station on the right flank all the way into the Boro box after Paddy McNair was caught off guard.

Somehow allowed to get a shot off, Roberts’ low effort was deflected wide by the legs of Dieng, who couldn’t have been too impressed with his protection.

That stunned Boro into action and a few moments later, Sam Greenwood capitalised on Trai Hume’s untimely slip on the corner of the box to fire off an angled shot that Anthony Patterson pushed out. Josh Coburn couldn’t quite turn home the rebound.

But there was no doubt Sunderland carried the greater threat. Another counter saw Ba running at the Boro defence, deciding not to try the audacious chip of Dieng from halfway even though he was miles off his line. In the end, Isaiah Jones had to drag him down, at the cost of a booking.

Then twice just before half-time, Dieng found himself clattered in the act of clawing away crosses that were hung high up to the back post, while Hume sent a shot over.

The Stadium of Light crowd certainly let Gillett know what they thought of him as he re-emerged for the second-half and Mowbray responded by taking off forward Mason Burstow and introducing attacking midfielder Adil Aouchiche.

The expectation was that Boro would be able to assert themselves a bit more and Patterson did brilliantly to deny Matt Crooks at point-blank range after Jones crossed from the right.

Boro’s numerical advantage was becoming ever-more apparent with space to exploit all over the pitch and it was little surprise when they broke the deadlock on 58 minutes then doubled the lead two minutes later.

Engel saw his initial shot from distance blocked but Boro kept the danger alive on the left. Dael Fry worked space before fizzing in a low cross to the near post and Greenwood connected perfectly to send the ball high into the net.

From their next attack, Jones skipped over Jack Clarke’s desperate sliding tackle down the right and cut back from the byline for Crooks to side-foot home.

It was all-too-easy for Boro, the pendulum completely swinging in the contest and Sunderland’s fans could only vent their frustrations at Gillett.

There was the very real prospect of further Boro goals and Jones lifted a shot narrowly over before scoring their third.

Capitalising on the wide open spaces afforded him, Jones embarked on another run into Sunderland’s box and showed real composure to wait for the perfect moment to roll the ball home.

That sparked a mass exodus of home fans who’d seen more than enough.

Sunderland, to their credit, kept pushing and Dieng saved from Aouchiche and Jenson Seelt late on.

But they were opened up again in the last minute as Forss finished from close range after Patterson saved from Emmanuel Latte Lath.