Chants of "McClaren for England" from the small but perfectly-formed band of Charlton supporters at the end were of course laced with irony, safe in the knowledge that the Middlesbrough manager has more than enough worries at club level to be contemplating his job prospects on the international stage.
After an embarrassing episode that saw McClaren disappear backwards through the advertising boards last season, the manager's stage in the press room had been strengthened to ensure there is no repeat.
Sadly for McClaren, his defence didn't appear similarly bolstered. In an excruciatingly dull encounter, the home side never looked like recovering from Dennis Rommedahl's crisp opener from 18 yards as the Dane latched on to a Danny Murphy pass just before the break.
Charlton's first top-flight victory on Teesside in 51 years was sealed 10 minutes from time as Chris Perry registered a rare goal, stealing in at the near post to divert a Murphy free-kick pulled back from near the by-line.
Darren Bent claimed his fourth Premiership goal in three starts in injury-time, outpacing two defenders to apply a confident finish to a Bryan Hughes pass to ensure Middlesbrough exited to a crescendo of jeers from disaffected supporters.
Murphy shone throughout, and at the risk repeating the fate of the last of his midfielder he talked up - Scott Parker, who left for Chelsea - Curbishley said: "In the first three games there's not been a better midfielder in the country." Sven Goran Eriksson instead chose an afternoon watching Parker at Newcastle United in preference to assessing Murphy's claims for a recall.
Despite this particular snub, the former Liverpool midfielder has not been totally discounted. Curbishley added: "I know Tord Grip was at our game against Wigan and I don't know if anyone was here today, but Danny shouldn't be discounted, he's still young." Murphy has helped orchestrate a renaissance which has resulted in three straight victories to start the season, Charlton's best in the Premiership.
"If we can get hold of the ball and pass it then we can do some damage," Curbishley added. "Perhaps we've been guilty of not believing in ourselves enough, but once the second goal arrived we were comfortable." Middlesbrough are yet to score in front of their own supporters this season, and clearly missed the injured Jimmy Floyd Hasselbaink.
McClaren is usually at pains to defend his players no matter what, but dropped the pretence on this occasion: "I'm very angry after that and I'm disappointed because that was unacceptable and I let the players know it was.
"There were no excuses and I don't blame supporters for their reaction. There's no way I can accept that level of performance."
Goals: Rommedahl (38) 0-1; Perry (80) 0-2; Bent (90) 0-3.
Middlesbrough (4-4-2): Schwarzer; Reiziger, Ehiogu, Southgate, Queudrue (Pogatetz, 46); Morrison (Mendieta, 46; Maccarone, 58), Boateng, Parlour, Downing; Yakubu, Viduka. Substitutes not used: Jones (gk), Doriva.
Charlton Athletic (4-2-3-1): Andersen; Young, Hreidarsson, Perry, Powell; Kishishev, Smertin (Hughes, 83); Rommedahl, Murphy, Thomas (Bartlett, 78); Bent. Substitutes not used: Myhre (gk), Spector, Fortune.
Referee: M Dean (Cheshire).
Booked: Middlesbrough Southgate.