George Horne's penalty put Warriors in front

Warriors will view the result as a huge opportunity loss to secure a place in the last eight of the competition.

Scott Cummings got Glasgow off to the perfect start when he dived over after great work from Tom Jordan but Harlequins struck back with three tries of their own to lead 21-7 at the interval.

After just ten minutes of the second half Glasgow were back level after a maul try from Johnny Matthews and a score from George Horne after some nice play from Kyle Steyn.

A penalty from George Horne put the visitors into the lead after an hour but despite sustained pressure, and a yellow card for Joe Marler after a dangerous tackle on Rory Darge, Warriors couldn't extend their lead.

With five minutes left on the clock Harlequins broke the Glasgow pressure to work their way down the field and eventually maul over for the winning score.

Warriors fought to the end but couldn't find the winning score and will be left wondering how they let the game slip from their grasp.