It took two attempts but this particular banana skin was finally binned by Derby County and in comfortable fashion.
There was rarely much doubt this FA Cup fourth round replay would go their way, particularly once a two-goal lead had been established before the break, and despite a brief scare when the well-backed Cobblers reduced the deficit just after half-time, Derby would go on to kill the tie off.
The Cobblers were positive throughout and could be proud of their efforts in pushing the Rams as far as they did both in the first game and in this one, but Manchester United at home is the prize for Derby who again sent a side away from Pride Park with nothing.
It took a while for either side to settle but Northampton had plenty of early possession, Andy Williams blazing an effort too high from a tight angle 11 minutes in with the first effort on goal of note.
Derby replied with Jack Marriott's shot from the edge of the penalty area rolling just wide of the post, then Tom Lawrence's 25 yarder was safely gathered by Northampton keeper David Cornell.
The Rams should have led on 20 when Wayne Rooney's divine through ball sent Marriott towards goal; he checked back and fed Chris Martin who opted to take a touch rather than shoot first time and although that sat Cornell on his backside, Town defender Michael Harriman was able to produce a last-ditch tackle to block Martin's shot out for a corner.
Then Marriott was released by an error from Scott Wharton but Cornell got down to block the Rams striker's shoourt as he entered the penalty area.
Kelle Roos then got down to push away Sam Hoskins' dangerous low centre as the Cobblers carried a degree of threat in the final third, but the Rams would finally strike on 28 minutes and it was an unlikely source who provided the goal.
Rooney's corner from the left was diverted high up in the air by defender Chris Lines at the near post and when the ball dropped back to earth, Andre Wisdom was on hand to fire home his first goal in seven-and-a-half years from a few yards out.
The second goal arrived seven minutes later as Scott Malone's pass was dummied by Martin which allowed Duane Holmes to take the ball in his stride and in on goal and he feinted to shoot before then sliding the ball past Cornell. Holmes' running was excellent throughout and he deserved his goal.
Wharton looped a header over the top from a Northampton corner five minutes before the break as the visitors looked for some inspiration, but the break arrived with a comfortable lead held by the hosts.
That lead was halved within 90 seconds of the second-half, as Northampton attacked down the left and Paul Anderson's low ball into the box was turned in by Nicky Adams from close range.
But Derby responded well and were 3-1 up on 52 minutes as Martin's dinked ball into the six yard box was headed towards goal by Marriott, Cornell delving the ball out from right on the goal line and Malone following up to net the rebound but the technology having already confirmed to the ref that Marriott's header was over the line.
Marriott nearly had another as his shot on the turn was deflected wide, before Northampton's Hoskins saw a powerful effort diverted over the top by a defender.
The fourth goal arrived on 77 minutes and it was from the penalty spot. After sub Jason Knight saw his shot saved by Cornell, Lawrence was fouled as he took possession of the rebound and headed towards the byline. Rooney stepped up and put the penalty low to Cornell's right and into the net despite the keeper getting close to it.
Northampton weren't done, earning a penalty of their own six minutes later when Curtis Davies clambered all over Andy Williams. Hoskins too dispatched his spot-kick well to reduce the arrears again.
But, other than a Hoskins dipper tipped over by Roos in stoppage time, that would be all they had left to offer as Derby saw the game out and a fifth round spot in early March awaits against Ole Gunnar Solskjaer's men.
Derby: Roos, Wisdom, Shinnie, Lawrence, Marriott (Sibley 78), Clarke, Martin (Waghorn 84), Holmes (Knight 69), Rooney (c), Davies, Malone
Subs not used: Ravas, Forsyth, Waghorn, Bogle, Bird
Northampton: Cornell, Goode (c), Hoskins, Watson, Adams (Martin 61), Williams, Lines (Pollock 59), Wharton, Oliver (Warburton 46), Harriman, Anderson
Subs not used: Arnold, Hall-Johnson, Roberts, Chukwuemeka
Ref: David Webb