Harlequins (9) 15
Pens: Jarvis (5)
Leicester (5) 21
Tries: Varndell, Bemand
Con: Burke
Pens: Burke (3)
Harlequins put up dogged resistance but were eventually overwhelmed by Leicester's relentless pressure.
When Tigers winger Tom Varndell went over in the first minute, the signs were not good for the home side.
But three Adrian Jarvis penalties put them ahead at the break only for Scott Bemand to score Leicester's second try after Will Skinner had been sin-binned.
Jarvis kept Quins in the game, but they remain joint bottom of the Premiership, winless from their first four games.
Harlequins director of rugby Dean Richards "There are a lot of positives. It doesn't give us the points we want but if we take the same intensity and passion and work on the small things the win will come.
"No-one here is panicking. In the first four weeks we have played some of the best sides in the Premiership.
"We have accepted that if it doesn't go our way, so be it, but we are not going to panic. It will turn round.
Leicester coach Richard Cockerill "We needed the points. If we had lost we would have been in the bottom four. We dug in and showed real character in the last 25 minutes of the game.
"We showed some character. We don't deserve anything by being Leicester Tigers, we have to earn it.
"We needed to win and in the end we probably deserved to win."
Harlequins: Duffy; Keogh, Luscombe, Deane, Monye; Jarvis, So'oialo; Jones, Hayter, Ross; Kohn, Spanghero; Easter, Skinner, Hala'ufia.
Replacements: Care for So'oialo (45), Richards for Hayter (60), Nebbitt for Ross (60), Evans for Kohn (60).
Not Used: Guest, McMullen, Brown.
Sin Bin: Skinner (54).
Leicester: G Murphy; J Murphy, Hipkiss, Vesty, Varndell; Burke, Ellis; Castrogiovanni, Chuter, White; Cullen, Kay; L Deacon, Moody, Corry.
Replacements: O Smith for G Murphy (44), Bemand for Ellis (53).
Not Used: Buckland, Holford, Crane, Jennings, A Tuilagi.
Attendance: 10,164.
Referee: Chris White (RFU).