Gary Madine's second-half penalty helped Sheffield Wednesday claim a Premier League scalp as they sent Fulham out of the League Cup.
Striker Madine coolly scored his first goal of the season after Chris Maguire was brought down by Cottagers defender Stephen Kelly.
Victory extended Wednesday's unbeaten run under boss Dave Jones to 18 games.
Fulham's Brede Hangeland thought he had equalised but saw his effort ruled out for offside.
Martin Jol's side have enjoyed a bright start to the Premier League season, scoring seven goals in their opening two games.
But they failed to show the same attacking prowess against the Owls, managing just one effort on target in 90 minutes.
Wednesday, currently second in the Championship after winning promotion in May, looked full of confidence and deserved to earn a third-round place for only the second time in 10 seasons.
Referee Paul Tierney had no hesitation pointing to the spot when Republic of Ireland defender Kelly clumsily bundled over Maguire as he skipped into the penalty area and Madine, who scored 18 goals for Wednesday last season, sent goalkeeper Mark Schwarzer the wrong way.
Fulham boss Jol, who made five changes from Saturday's 3-2 defeat at Manchester United, finally saw a response from his team and skipper Hangeland did have the ball in the Owls net. But his 63rd-minute header from a Matthew Briggs cross was ruled out by the assistant referee's flag.
And the home side came within a whisker of making victory safe in the 77th minute, only for Schwarzer to brilliantly tip Nejc Pecnik's 20-yard shot on to the bar.
Sheffield Wednesday boss Dave Jones: "There's a real feel-good factor around the place at the moment.
"But you can't take it for granted otherwise this game will kick you in the teeth.
"So we just have to keep doing what we're doing, and hopefully this will continue."