It took a second-half comeback but Charlton clawed back a two-goal deficit to salvage a third-round replay with Oxford United.
Chris Powell must surely have read the riot act to his players at the break as they were tasked with turning around the visitor's first-half strikes. But the Addicks duly responded as Michael Morrison and Yann Kermorgant saved the day to force a redo in Oxfordshire.
Powell, celebrating his three-year anniversary at the Valley helm, named a strong starting XI perhaps emphasising his wish for Charlton to buck the trend and embark on a meaningful cup run.
Ben Hamer made his first start since suffering ankle ligament damage prior to November's rearranged clash with Doncaster Rovers.
And there was a first start for Jordan Cook since the club's previous league cup with Oxford at The Valley in August.
All the talk before the game surrounded The Valley's playing surface. And, of course, the puddingy pitch threatened to disrupt the flow of the game.
The first sight of goal came from the Addicks in the form of the skipper.
Lawrie Wilson found space on the right and delivered for Johnnie Jackson, but controlled header looped just wide.
A quiet opening period was interrupted by a goal after 13 minutes. But, unexpectedly, it came courtesy of the visitors.
With the U's winning a corner, the delivery came in low and, with Johnny Mullins making scuffed contact to divert an effort goalwards, Michael Morrison's attempt at a clearance saw it wrong-foot Ben Hamer and dribble into the bottom left-hand corner.
Five minutes later the Addicks had a glorious opening.
When Lawrie Wilson was given the freedom of the right-flank, he sent in a dangerous cross to the far post.
With Kermorgant lurking with intent, all those present in SE7 expected the Frenchman to unleash a trademark volley.
Instead, he opted to cushion a volleyed pass across goal. His attempted assist was dealt with immediately allowing the visitors to clear their lines.
Charlton were struggling to get even a sniff of an equaliser. And after 24 minutes an uphill climb became a mountainous struggle as Chris Wilder's men went two goals in front.
Jordan Cousins took one touch too many as he dawdled in his side's defensive third.
His hesitance allowed Mullins time to dispossess which saw the ball run free. Quick as a flash the ball was laid on for Scott Davies who steamed towards goal with just Hamer to beat.
And Davies finished confidently to send the travelling fans from Oxfordshire into raptures.
The upset was on. And with 35 minutes on the clock it very nearly got even better for the visitors when Sean Rigg saw his rasping drive from outside the box sail narrowly over the crossbar.
The Addicks were lacklustre and their cup hopes were sinking in the mud rapidly.
Penalty shouts echoed around the sparsely populated Valley just before half-time. But although the ball did clearly strike the arm of Tom Newey he did not know too much about it and any decision which saw the referee point to the spot would, indeed, have been very harsh.
With the loose ball bouncing back to Bradley Pritchard via Newey's arm the midfielder drilled a low shot straight at Ryan Clarke in the Oxford goal.
That was the last piece of action in the first-half and it did not make for good hearing at the half-time whistle as the home side left the field to a chorus of boos.
The second-half, however, began more positively as the Addicks went about trying to rescue the cup tie.
On the front-foot, they went on the attack. Kermorgant hit a shot straight at Clarke before tenacity from Simon Church and Jordan Cousins won Charlton corners.
And it was from a set-piece on 53 minutes that Powell's side got a footing back in the tie.
Jordan Cook sent in the corner which was met emphatically by a non-nonsense header from Morrison which rippled the net to make it 2-1.
With the job only half-done, the Addicks continued on the offence.
Pritchard worked hard to keep the ball from going for a goal-kick and placed the ball straight back into the mix.
As it bobbled about near the penalty spot, Jackson finally hit a half-volley which produced a good save from Clarke.
Hamer was forced into a save down the other end on the hour mark as James Constable looked for the bottom corner with a header.
But getting down well, the returning custodian tipped the ball out for a corner.
Six minutes later Wiggins tried for an audacious first-time, angled chip from the edge of the box but his speculative effort dipped over.
Danny Green entered the fray with just over 20 minutes remaining. And the winger made an immediate impact.
His ability to deliver from wide provided Powell's side with an outlet and his dangerous crosses caused havoc more than once as Charlton continued to push.
Into the final ten minutes and the home side had their best chance yet to equalise.
Substitute Callum Harriott crossed for Jackson in space, but the captain watched as his header flew agonisingly wide of the left-hand upright.
But it mattered not because within a minute the Addicks were level.
And it was Green who received the plaudits thanks to his fine work in the build-up.
Skinning the full-back, he followed up with one of his havoc-causing crosses. And, with Kermorgant on hand in the box, there was no doubt.
The burly Breton adjusted well to send a scissored volley into the net to complete the comeback.
Not content with the draw, Rhoys Wiggins ventured forward looking to end the tie.
His first effort was hit straight at Clarke but his second rasped past the post allowing Oxford to live another day.
Deep into injury time, it was nearly Harriott the hero as the winger got on the end of Wilson's deep cross.
Waiting patiently at the back post he directed his header goalwards and with Clarke beaten, David Hunt got a vital final touch to put behind for a corner.
And that was all she wrote for what was ultimately an entertaining cup tie.
The two sides will do it all again at the Kassam Stadium meaning the Addicks now face a run of four consecutive games on the road, and five should they get past Oxford in the replay.
Charlton: Hamer; Wilson, Wiggins, Wood, Morrison; Pritchard (Green 67), Cousins, Jackson, Cook (Harriott 78); Church (Pigott 78), Kermorgant.
Subs (not used): Pope, Hughes, Evina, Dervite.
Goals: Morrison (53), Kermorgant (82)
Oxford: Clarke; Hunt, Newey, Mullins, Raynes; Wright (c), Davies (Williams 87), Marsh (Smalley 53), Ruffels; Constable (Kitson 78), Rigg.
Subs (not used): Rose, Long, Bevans, O'Dowda.
Goals: Mullins (13), Davies (24)