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The Cottagers were on the back foot for the majority of the match, but Gudmundsson could do nothing when a Sasa Lukic corner ricocheted off his head and into his own net.

Leeds was on top in the first half, with Dominic Calvert-Lewin heading straight at Bernd Leno before Sean Longstaff struck the woodwork just before the break.

While it could not find a way past Leno, with Brenden Aaronson going close at the start of the second period, it restricted the hosts from attempting a shot until the 58th minute.

Fulham's first chance came through a Harry Wilson free-kick, and it pushed on from there as Rodrigo Muniz and Kevin – on his debut – were denied by Karl Darlow, who was finally beaten in the fourth minute of additional time by the wrong-footed Gudmundsson.

The win moved Marco Silva's side up to 10th, while Leeds is one point behind in 14th after a heartbreaking finish.

"Definitely a tight game, very difficult in some moments to break them down," Silva said.

"You felt straight away the changes that Daniel [Farke] made to his team were to be much more conservative out wide, control better our left-hand side – and they did it.

"With good organisation, it is not easy to break them down. In the first half, we were probably too slow. We did not take too many risks. I think second half we were much better, more dynamic.

"In these moments, you can have a bit of fatigue, and in the last 30 minutes, we did create some dangerous moments around their box.

"An own goal in the last minute of the game, so we have to feel a bit fortunate. A nice feeling for us, a difficult feeling for Daniel and the Leeds boys, but that is part of the game.

"It was important for us to keep a clean sheet because we need to create this habit, and it allowed us to go on and try to win the game."

Leeds, meanwhile, has now lost each of its past nine Premier League away games in London.

Slightly worrying for boss Daniel Farke will be the fact that Leeds has scored just one goal in the top-flight so far this season against Everton on matchday one, with this being its fewest after four games of a league campaign in the club's history.

It also had chances to win it, with Sean Longstaff's driven effort skimming the bar in the first half, but despite his disappointment, Farke noted there were positives to take from the performance.

"Yeah, of course, as we all know, sometimes football can be cruel and can be heartbreaking," he said.

"Sometimes you are on the lucky side, and [on Saturday] we were definitely on the unlucky side. I feel for the lads, after a couple of difficult weeks, we showed an excellent away performance – we were rock solid.

"Football can be like this, but I'm just proud of the performance and how we dealt with the offensive threats of Fulham, how controlled we were. For 65 minutes, we looked the side more likely to win this game."

On the Gudmundsson own goal, he added: "I'm working a long time in football, but such a strange situation, I've not seen. Even a striker would struggle to score such a header. I think maybe we was concentrated on the blocking and lost his balance and was then a bit surprised.

"It's difficult to explain. Of course, he's the most heartbroken in the dressing room, so he doesn't need any criticism from me. He needs an arm around the shoulder."