Hull withstood a late fightback to send the Broncos spinning to their first defeat at Griffin Park this season by 20-16.
John Kear?s side, who were missing a host of players through illness, recovered from a disastrous start which saw them 10-0 down after seven minutes to completely turn the game on its head with 20 unanswered points.
The home side finished strongly but had left themselves a mountain to climb after struggling for almost an hour to keep hold of the ball.
The Broncos came out of the blocks on fire with Tyrone Smith sending Nick Bradley-Qalilawa into the corner with less than a minute on the clock.
The hosts did not have to wait long for their second try either, Luke Dorn throwing a delightful dummy to ghost around his marker in the seventh minute, with a fifth home win of the season looking on the cards.
Hull got back into the game in the 13th minute Richard Swain and Paul McNicholas combining to send Gareth Raynor into the corner after the Broncos gave away a penalty at a scrum for dissent.
Hull drew level after 19 minutes Raynor using some deft soccer skills to keep Paul Cooke?s kick in play and set up Kirk Yeaman who touched down.
Hull FC coach John Kear has confirmed that hooker Richard Swain faces a long injury lay-off after breaking his arm inflicting London?s first home defeat of the season.
Swain was taken off towards the end of the game and Kear revealed the news was as bad as first feared.
?Richard has broken his arm and that is a blow,? he said.
?He?s been the corner stone of our team for the last two seasons but these things are part and parcel of a high-impact game.
?I thought that our bench changed the game to tell you the truth, we were struggling until I brought on Garreth Carvell and Stephen Kearney.
?It was a very exciting game of rugby league and certainly didn?t do anything for the heart strings, a very tense game like that.
?We stayed in the sheds for the first 10 minutes and London, who are a very fluid side and ask a lot of questions, had posted 10 points before we had woken up.
?I think it is all credit to the team that they showed great resilience to score 20 unanswered points before we had to hang in there at the end.?
Amazingly the visitors then took the lead after 26 minutes Cooke supplying the pass for Stephen Kearney to take advantage of poor marking to cross the whitewash.
The Broncos found themselves on the back foot largely thanks to their inability to keep hold of the ball through a series of knock-ons.
Then a minute into the second half Danny Brough extended Hull?s lead to eight points with a penalty from right in front of the posts.
After 50 minutes Brough kicked his fourth successive goal of the match to take his side to lead into double figures, leading 20-10.
The Broncos were reduced to 12 men when Lee Greenwood was sent to the sin bin after he tried to slow the game down following a Raynor 80-metre break.
The Broncos tried to battle back with Joe Mbu and Lee Hopkins denied tries within 60 seconds of each other on the hour mark.
Mbu then set up an exciting finish six minutes from time when he squeezed over the line from close range but Hull hung on for the victory.
London (10) 16. Tries: Bradley-Qalilawa, Dorn, Mbu. Goals: Sykes 2.
Hull (16) 20. Tries: Raynor, Yeaman, Kearney. Goals: Brough 4.
London: Lucky Luisi, Wells, Smith, Sykes, Bradley-Qalilawa, Dorn, Leuluai, Trindall, McLinden, Stephenson, Haumono, Hopkins, Mbu.
Replacements: Greenwood, Highton, Lolohea, Tookey.
Hull: Tony, Barnett, Yeaman, Eagar, Raynor, R. Horne, Brough, Dowes, Swain, Thackray, McMenemy, McNicholas, Cooke.
Replacements: Kearney, Higgins, Carvell, Whiting.
Referee: R Lawton (Barnsley)
Thanks to: http://www.superleague.co.uk for another excellent article.Like