Hooker Sam Riley scored a late try as Harlequins defeated Glasgow Warriors in a thriller to book their spot in the Investec Champions Cup quarter-finals.

Andre Esterhuizen, Marcus Smith and Cadan Murley crossed for a 21-7 lead.

Glasgow hooker Johnny Matthews and George Horne sparked the game back into life, but Riley responded to hand Harlequins a historic victory.

This was Quins' first knockout win in Europe's top-tier competition in their history, with the prize a quarter-final against Bordeaux Begles or Saracens next weekend.

An away win for Saracens on Saturday, who suffered a club record European defeat by Bordeaux during the pool stages, would mean a home tie for Harlequins in their first quarter-final in 11 years.

Smith stars as Quins hold on

Franco Smith's starting XV contained 11 Scotland internationals and it did not take them long to show their class, with lock Cummings powering his way over to reward Glasgow's fast start in attack.

Wet and difficult conditions did not prevent both sides from playing in the first half as Quins turned down shots at goal to seek the maximum reward.

Their bravery finally resulted in points, as Marcus Smith's cross-field kick was brilliantly picked up by Esterhuizen on the wing.

The England playmaker missed the opening three rounds of the Six Nations because of injury, but came on to kick the winning drop-goal against Ireland in round four, before finishing sharply for a try in defeat by France in Lyon.

His impact left England wondering what could have been if fit for the whole championship, and his dancing feet to grab his side's second try once again showed his individual brilliance.

The 25-year-old then turned provider with some sharp hands to send Murley over untouched.

Glasgow have scored the most tries from mauls across European leagues this season and they turned to this lethal weapon after the interval as Matthews went over to start their fightback.

Horne's try quickly followed before he knocked over a penalty to regain their lead.

But Quins found their composure and opted for a driving maul instead of potentially levelling the game with a penalty, and the brave call was rewarded with the winning try.

Added to his touches in attack Smith was impeccable off the kicking tee, with three conversions in the first half and the fourth with minutes remaining, keeping Glasgow out of three-point range.

'That's a monkey off the back' - Smith

Player of the match Smith, speaking on TNT Sports about relinquishing a 14-point half-time lead: "Whenever we're ahead, we seem to let the opposition in; that's something we're working on.

"We're still not where we want to be, but we've got another European knockout now, which is exciting.

"In the last two years we've fallen at this hurdle, so that's a monkey off the back. We'll enjoy tonight because we haven't done it before.

"The biggest thing was to stick to the plan. Glasgow are an excellent team, and massive credit goes to the forwards for mauling over at the end there."

Line-ups

Harlequins: Green; Lynagh, Beard, Esterhuizen, Murley; Smith, Care; Baxter, Walker, Collier, Herbst, Hammond, Lewies (capt), Evans, Dombrandt.

Replacements: Riley, Marler, Lewis, Launchbury, Trenholm, Lawday, Green, Anderson.

Sin-bin: Joe Marler (62)

Glasgow: McKay; Steyn (capt), McDowall, Tuipulotu, Rowe; Jordan, Horne; McBeth, Matthews, Z Fagerson, Williamson, Cummings, M Fagerson, Darge, Dempsey.

Replacements: Hiddleston, Kebble, Sordoni, Manjezi, Miller, Venter, Dobie, Weir.

Sin-bin: Sione Tuipulotu (33)

Referee: Tual Trainini (France)