Harlequins remained unbeaten in this year's Anglo Welsh LV= Cup when they Premiership rivals London Welsh 23-6 at the Twickenham Stoop on Saturday.
Premiership newcomers London Welsh have yet to win a match in their debut season of the Anglo Welsh Cup.
Harlequins went to the top of Pool One but it didn't come easily in a scrappy match full of positive intentions but short on execution.
The home side dominated the set scrum but in the loose the visitors were the masters and their hard-working pack were very unlucky to come away with no reward.
Prop Mark Lambert's try helped Quins to a 10-6 lead at half time.
Ben Botica added the conversion and two penalties after the break to give Quins breathing room before hooker Dave Ward a simple try from a fluffed Welsh line-out sealed victory.
Final Score Harlequins 23 (10) London Welsh 6 (6)
Tries: Lambert, Ward
Cons: Botica 2
Pens: Botica 3
Pens: Davies 2
Referee: Neil Hennessy (Wales)
Assistant referees: Stuart Terheege (England), Andrew Pearce (England)
Timekeeper: Bob Ockenden (England)
Assessor: Gary Welsh (England)
Harlequins: 15 Ollie Lindsay-Hague, 14 Seb Stegmann, 13 Matt Hopper, 12 Tom Casson, 11 Sam Smith, 10 Ben Botica, 9 Karl Dickson, 8 Tom Guest, 7 Luke Wallace (c), 6 Joe Trayfoot, 5 Charlie Matthews, 4 Sam Twomey, 3 Will Collier, 2 Dave Ward, 1 Mark Lambert.
Replacements: 16 Harry Allen, 17 Darryl Marfo, 18 Kyle Sinckler, 19 Jack Clifford, 20 Harry Sloan, 21 Jordan Burns, 22 Louis Grimoldby, 23 Ross Chisholm.
London Welsh: 15 Tom Voyce, 14 Nick Scott, 13 Sonny Parker, 12 Seb Jewell, 11 Phil Mackenzie, 10 Gordon Ross, 9 Alex Davies, 8 Adam Balding, 7 Michael Hills, 6 Ed Jackson, 5 Kirill Kulemin, 4 Adam Brown, 3 Paulica Ion, 2 Dan George, 1 Tom Bristow.
Replacements: 16 Gareth Evans, 17 Billy Moss, 18 James Tideswell, 19 Martin Purdy, 20 Daniel Browne, 21 Luc Jones, 22 Joe Ajuwa, 23 Tom Arscott.