|Harlequins (14) 14|
|Tries Dombrandt, Chisholm Cons: Smith 2|
|Worcester (9) 19|
|Tries: Shillcock Con: Lance Pens: Lance 4|
Jono Lance kicked 14 points as Worcester kept Harlequins scoreless in the second half to record a hard-fought victory at a rain-soaked Stoop.
Alex Dombrandt and Ross Chisholm scored tries within five first-half minutes, with Marcus Smith converting both, to give Quins a commanding 14-3 lead.
Lance then struck two penalties to reduce the gap to five at the break.
Jamie Shillcock's 68th-minute try was converted by Lance, who added a last-minute penalty to seal the win.
Australian stand-off Lance was brought into the team as skipper after a hand injury to Duncan Weir, in a Worcester side also missing key men Ryan Mills, Chris Pennell, Francois Hougaard and forwards Marco Mama and Nick Schonert.
After his early penalty put Warriors ahead, Harlequins seized the initiative, with powerful number eight Dombrandt picking a gap in the defence to cross.
Ross Chisholm added a second try after Shillcock lost the ball in contact with Francis Saili, allowing the full-back to kick the ball on and touch down.
Quins were penalised twice for offside in the final 10 minutes of the opening period, allowing Lance to reduce the arrears from the tee.
Marcus Smith missed an early second-half penalty as Quins struggled to break down the visiting defence, as the game became more attritional in wretched weather conditions.
But, from a spell of Warriors pressure, scrum-half Michael Heaney fed Shillcock, who went over in the corner to level at 14-14 - and Lance's boot did the rest.
Harlequins head coach Paul Gustard:
"The first 15 minutes were very good but then we just made too many errors and weren't able to maintain field position or possession.
"I don't think we came on to the ball hard enough or ran with enough purpose. We had enough to win but it was a nip-and-tuck fixture and we came out second best.
"There's no point feeling sorry for ourselves. We're not a bad team, but we're not playing as well as we can at the moment and we've got to dig ourselves out of it.
"We'll look at what we're doing and how we can improve in terms of selection and playing style."
Warriors director of rugby Alan Solomons told BBC Hereford & Worcester:
"We should have won last weekend, but to come here - in such poor weather conditions - and recover from being 14-3 down was exceptional.
"Both sides were committed but, on the balance of play, we deserved the win.
"It was a question of field position and as the game went on that became imperative. Errors were a major factor but we played the game and conditions really well.
"We're sitting on nine points now. I would like us to have more but I'm happy with where the lads are at the moment."
Harlequins: Chisholm; Murley, Lang, Saili, Ibitoye; Smith, Landajo; Botta, Elia, Collier, Young, Cavubati, Chisholm (capt), Evans, Dombrandt.
Replacements: Baldwin, Auterac, Kerrod, Lamb, Lawday, Saunders, Campagnaro, Goneva.
Replacements: Goneva for Murley (56), Lawday for Chisholm (56). Baldwin for Garcia Botta (58), Auterac for Elia (58), Kerrod for Collier (61), Lamb for Cavubati (74), Saunders for Landajo (74).
Not used: Campagnaro.
Worcester Warriors: Shillcock; Nanai, Venter, Beck, Fidow; Lance (capt), Heaney; Waller, Annett, Palframan, Bresler, G Kitchener, Hill, Lewis, Du Preez.
Replacements: Fatialofa for Kitchener (56), van Velze for du Preez (56), Taufete'e for Annett (56), Lawrence for Beck (62), Black for Waller (62), Carey for Palframan (65).
Not used: Kitto, Humphreys.
Referee: Matthew Carley.