Newcastle captain Alan Shearer put his penalty misery of seven days ago behind him to fire his side into the top three in the Barclaycard Premiership.
Shearer struck from the spot on the half-hour against Derby after Laurent Robert's blistering run had been crudely interrupted by Chris Riggott, sending Mart Poom the wrong way to claim his 98th goal in a black-and-white shirt.
But Derby left St James' Park knowing they should have been taking something with them after Fabrizio Ravanelli saw a 57th-minute spot-kick saved by the excellent Shay Given.
That would have been just reward for the Rams, who more than played their part in a game which never really hit the heights an expectant public craved.
Newcastle were constantly troubled by Ravanelli and Benito Carbone and were rarely able to carve the holes they needed to prosper at the other end.
County, spurred on by captain Craig Burley, did not play like a bottom-four side and were less wasteful than their hosts but just could not find a cutting edge.
Both managers named unchanged sides but sent their players out with very different messages.
Bobby Robson's men knew they had to improve on the display they put on in the 3-1 defeat by Fulham last weekend, while Colin Todd wanted more of the same from a side who had secured only their second Premiership win of the season against Southampton.
But the visitors, prompted by Burley in the middle of the park and experienced Italian front men Ravanelli and Carbone, took the game to the Magpies.
Given was called upon in the fifth minute to keep out a Ravanelli drive and then needed to be at his best when Darryl Powell, capitalising on an error by Rob Lee, burst through but could not round the Irishman.
Carbone went close two minutes before the break with a dipping right-foot volley.
But in the meantime Newcastle had finally managed to rouse themselves from the lethargy and carelessness which had characterised their opening.
A beautiful Shearer chip aside, they had managed to create little until Frenchman Robert - a virtual spectator early on - turned up on the right wing and surged into the box before tempting Riggott into a rash tackle.
Referee Rob Styles had no hesitation in pointing to the spot, and Shearer stepped up to send Mart Poom the wrong way.
The goal sparked something of a United revival as Nolberto Solano and Robert in particular got the bit between their teeth to leave Derby feeling a little aggrieved to be behind but knowing there was surely more to come from them after the break.
The second half began in similar fashion to the first as the visitors counter-attacked with vigour and some style, while United failed to make the most of their possession.
They should have been made to pay with 57 minutes gone when Ravanelli's clever turn lured Andy O'Brien into an ill-advised challenge which had the referee pointing to the penalty spot for a second time.
Given was booked for his protests but then steadied himself before diving low to his left to keep out Ravanelli's spot-kick.
Despite their stuttering form and Derby's stubborn resistance, the home side continued to make chances Ñ-Robert firing just wide from distance and Youl Mawene getting in a fine block to keep out Bellamy's diving header from Shearer's cross.
The Welshman had a good chance to wrap up the points 13 minutes from time when Poom could only parry Gary Speed's shot, but Danny Higginbotham was on hand to close him down swiftly.
Newcastle desperately needed a second goal for insurance and they went close twice within minutes as Hughes smashed a right-foot shot over the bar after a rare foray up field and Shearer saw a 25-yard effort turned away by Poom.
But they ended the 90 minutes defending for all they were worth to claim a hard-fought victory.
