Paulo Di Canio insisted he was anything but content after watching his Swindon side end a three-game winless run in style at Stevenage.
Goals from Matt Ritchie, Raffaele De Vita, Miles Storey and Adam Rooney inflicted a heaviest-ever Football League defeat on high-flying Boro - their first at home this season.
Three goals came in an impressive first-half performance in which the Robins might have scored more, with Tommy Miller having a penalty saved by home goalkeeper Steve Arnold. But rather than leaving Di Canio delighted, the display only served to highlight to the Italian what his players had failed to deliver in recent weeks.
"The performance was good, I'm happy with the three points, but obviously I'm not completely happy. I'm more angry than ever. You can imagine why," said the Swindon boss.
"I've asked my players, why did they switch off for three or four games. Because the secret wasn't that we played better as a team - that was clear. But because every individual behaved 120 per cent. Fortunately, thanks to the players, we've scored four very good goals - which we deserved. That's why I'm angry with them, because they're capable of this.
"Yes, it's the best performance this season - 4-0 away at one of the best sides at the moment. I cannot sound arrogant. It was 4-0 and fully-deserved but we missed a penalty and created another three or four clear chances.
"Against Coventry recently we created the same number of chances - seven, eight, 10 clear chances - and yet we only scored twice. Obviously, the more chances you create the more goals you'll score. Here we took our opportunities and I'm delighted about that."
It was a disastrous day at the office for Boro, who slipped out of the automatic promotion places - and boss Gary Smith admitted his side had been outclassed.
"They started brighter than us, sharper than us and looked more of a goal threat. And there were far too many of our players who were below par, and Swindon took advantage of that," said Smith.
"I hoped the penalty save was going to galvanise a few of the guys into a little bit more of a performance, but in truth we never really got going. I have to give a hell of a lot of credit to Swindon for that. They pressed the ball well, they worked tirelessly to win it in that central area, and not many teams have been able to out-compete us."