A sparkling hat-trick from Clint Dempsey dashed Charlton’s hopes of springing a surprise as Fulham romped into the FA Cup fourth round this afternoon, although the final margin of their victory certainly flattered the Premier League side.

Chris Powell’s League One leaders were well-organised and enterprising. Roared on by 7,000 fans, they might have taken an early lead but for John Arne Riise scrambling away Danny Hollands’ header from underneath his own bar at a Johnnie Jackson corner. Even after Dempsey had clinically rolled Fulham in front, the visitors’ heads didn’t dip. Only a splendid double save from David Stockdale, who emphasised his England credentials by denying Bradley Wright-Phillips and Danny Green in quick succession, preserved Fulham’s lead before the home side’s superior fitness and sharpness told in the game’s final quarter.

Powell had spoken of the need to frustrate the home side early on, but Fulham were in front as early as the eighth minute. Danny Murphy, roundly booed by the visitors supporters throughout, slide a through a square Charlton back-line and, although a massive deflection, saw the ball fall invitingly for Dempsey, the American midfielder coolly skipped in to beat stand-in goalkeeper John Sullivan and open the scoring.

Martin Jol had stayed true to his pledge of picking his strongest possible side, but it was the one inclusion from the team that beat Arsenal on Monday, who stole the show. Teenager Kerim Frei tormented poor old Chris Solly down the Fulham left with tricky footwork and the confidence to go both inside and outside the full back. Moussa Dembele had a largely quiet afternoon but drew a splendid save from Sullivan with low drive, while Dempsey and Riise all went close with drives from distance. For all of Fulham’s first half possession, there were a little timid in front of goal.

Charlton had already tested Stockdale intermittently in the first period, with the Fulham goalkeeper backpeddling to save from Yann Kermorgant and thwarting Wright-Phillips with his feet at the near post, but really stepped up the pressure in a stirring second half spell. A lovely pass from Kermogant freed Wright-Phillips but Stockdale spread him brilliantly to save, before the former Darlington goalkeeper did brilliant to turn a rising effort from Green over the crossbar.

Jol acted swiftly, replacing the tiring Frei with Damien Duff, and the Irish winger almost had an immediate impact. Working a clever one-two with Bobby Zamora, Duff cut in from the right and his low save was well parried by Sullivan, who had earlier sprung away to his right to save a deflected Murphy shot. Fulham were suddenly looking a lot more threatening on the break and the goal that put the contest beyond Charlton arrived just after the hour. A flowing Fulham move saw Dempsey and Bryan Ruiz link beautifully before Dempsey surged onto the Costa Rican’s perfectly weighted return ball and clipped a clever finish over Sullivan and into the far corner.

Fulham were now beginning to show some of their Premier League class. Ruiz stooped to flick a Kelly cross wide with his head and Zamora found half a yard of space in the box, before a fine saving challenge from Michael Morrison diverted the shot over the bar. To their immense credit, Charlton still poured forward. Wright-Phillips should have down better after a goalmouth scramble and Riise was again on hand to block a Kermorgant shot.

Jol’s side added a far more convincing look to the scoreline in the final ten minutes. Sullivan was penalised for bringing down Ruiz after the former FC Twente winger tricked his way past Cedric Evina, which allowed Dempsey to belt home his third from the penalty spot. Duff then earned a fitting reward for his lively cameo with the fourth: a deflected shot from the edge of the box that Sullivan had little chance of stopping.

FULHAM (4-1-4-1): Stockdale; Kelly, J.A. Riise, Hangeland, Senderos; Murphy (Sidwell 81); Dembele (Kasami 85), Dempsey, Frei (Duff 59), Ruiz; Zamora. Subs (not used): Etheridge, Hughes, Gecov, Sa.

GOALS: Dempsey (8, 61, pen 81), Duff (87).

CHARLTON ATHLETIC (4-4-2): Sullivan; Solly, Wiggins (Evina 72), Taylor, Morrison; Green (Wagstaff 72), Hollands (Hughes 85), Pritchard, Jackson; Kermorgant, Wright-Phillips. Subs (not used): Pope, Cort, Euell, Hayes.

BOOKED: Green.

REFEREE: Phil Dowd (Stoke-on-Trent).