Quins coach Richard Hill said: 'We had a tight game against Leicester in the league a couple of weeks ago and we lost, even though they were without their better players.
'This performance was nowhere near where we want to be. There is a lot to do technically and of course there is also going to be a psychological block against Leicester.'
Quins had the pleasure of scoring the only try of the match on Saturday through lock Steve White-Cooper.
However, John Steele, Northampton's director of rugby, would have been happier if his team had chosen to kick a couple of first-half penalties, instead of tapping the ball and looking for touch.
Steele said: 'They represented a possible six points and we only lost by five.'
