Harlequins upset Hull at a bitterly cold KC Stadium to claim their first victory of the Super League season.
Hull (6) 6
Harlequins (10) 10
Tries: Leuluai, Smith
Despite not troubling Hull's line in the second half, their outstanding defence kept the hosts scoreless.
Quins scored two tries in five minutes in the first half when Thomas Leuluai scooted over from dummy-half and Luke Dorn sent Tyrone Smith to the corner.
Shaun Briscoe's 50m effort gave Hull hope, but it was the only time they managed to breach Quins' defence.
Hull looked anything but the league's highest try-scorers going into the game in a performance littered with handling errors and poor decisions with ball in hand.
After Quins had surged into a 10-0 lead with their quick-fire double, Hull were slow to respond and struggled to gain any significant field position.
Kirk Yeaman spurned a chance to post his eighth try of the season when he knocked on over the line.
But in spite of their profligacy, they were only four points down when Briscoe seized on a static defence to race to the left corner, Danny Brough converting from the touchline.
Hull probed with greater purpose in the second half but were twice
denied scores when Yeaman's score was chalked off for an indiscretion and Motu Tony was dragged into touch.
Leuluai then denied Richard Horne with a crunching last-ditch tackle and Yeaman then went without the ball after Paul Cooke had fashioned a half-chance.
As Harlequins began to close the game out, Jamie Thackray was held up over the try-line, before Matt Gafa collected Horne's kick in goal despite intense pressure from the onrushing Richard Whiting to seal the win.
Hull coach John Kear
"It is an understatement to say that I am very disappointed. As a group we are intensely disappointed.
"It was an under-par performance, especially the slow start that gifted Harlequins 10 points. The tries we conceded were soft tries.
"From then we were always struggling to get it back and some of our execution was well below-par, there was a lot of poor decision-making and an inconsistent kicking game."
Harlequins coach Tony Rea
"The conditions made everyone change game-plan and tonight was more about getting a result.
"There was some real good commitment to working together as a unit.
It is more of a positive that they didn't score in the second half than it
is a negative that we didn't.
"We were never in a position to score. The important thing in the game was to take our chances and we did that, all two of them."
Hull: Briscoe, Tony, Domic, Yeaman, Raynor, R. Horne, Brough, Dowes, Swain, King, Radford, McMenemy, Cooke. Replacements: Thackray, Carvell, Chester, Whiting.
Harlequins RL: Lucky Luisi, Gafa, Sykes, Smith, Bradley-Qalilawa, Dorn, Leuluai, Mills, Weisner, Tookey, Purdham, Hopkins, Temata. Replacements: Williams, Haumono, Heckenberg, Lolohea.
Referee: A Klein (London).