Harlequins produced a spectacular second-half comeback to increase Hull FC's problems at the foot of the table.

The Londoners fought back from 16-6 down at half-time with tries from Julien Rinaldi, Mike Worrincy, Chris Melling (2) and Tony Clubb.

Adam Dykes was the catalyst for Hull's fast start with Richard Whiting, who broke his leg late on, Tommy Lee and Danny Washbrook all scoring.

But Clubb got one back before the break to spark Quins' second-half surge.

Hull flew out of the blocks as Australian Dykes tested Quins' full-back Jon Wells with a bomb into the corner which allowed Whiting to touch down after two minutes.

Another high kick from Dykes after 27 minutes gave winger Rikki Sheriffe problems and allowed Mike Burnett to clean up and feed Lee for the score.

Hull raced further ahead when stand-off Washbrook crossed after slick handling from Dykes as the visitors took control.

But Quins hit back before the hooter when a series of penalties allowed replacement second-rower Clubb to burrow his way over from short range to cut the deficit.

Quins, orchestrated by Australian stand-off Scott Hill, picked up where they left off after the break when Rinaldi intercepted Craig Hall's pass and ran home from 30 metres.

Kirk Yeaman kept Hull ahead with a storming 85m run after 50 minutes but Quins ran riot late on.

Worrincy crashed over six minutes later before Melling scored straight from the kick-off as the hosts went 24-20 ahead.

Clubb dragged three defenders over with him after 68 minutes before Aussie Matt Sing pulled one back for Hull.

But Melling sealed the victory for Quins to leave Hull second from bottom of the Super League.

Harlequins coach Brian McDermott:

"Scott [Hill] was very influential for us - he looked quick and sharp.

"I thought we were poor and it was just a few individuals who stood up for us.

"We lacked a bit of intensity and urgency but we managed to turn it around in the second half.

"It was very important for us to get the win - usually I am talking about performances but it was important for us to do what was required when needed.

"We have been playing a lot better in the last three weeks but winning was the main thing and that is what we achieved."

Hull FC coach Peter Sharp:

"We were mentally and physically fragile. The try just before half-time and the try just after did the damage.

"We are just low on confidence - we have got a lot of kids playing and we have got a few people who just can't get the job done at the moment.

"There is a lot of rugby left in the season but if we want to be up there we have to improve."

Harlequins: Barker, Clubb, Gafa, Grayshon, Haggerty, Hill, Howell, Mbu, Melling, Orr, Paul, Randall, Rinaldi, Sharp, Sheriffe, Temata, Ward, Wells, Worrincy.

Hull: Berrigan, Burnett, Byrne, Briscoe, Dowes, Cusack, Dykes, Hall, Houghton, Lee, Manu, Radford, Raynor, Sing, Thackeray, Washbrook, Whiting, Wheeldon, Yeaman.