|Harlequins (24) 48|
|Tries: Marchant, Lang, Smith 2, Care, Dombrandt Cons: Smith 6 Pens: Smith 2|
|Wasps (22) 46|
|Tries: Bassett 2, Odogwu, Robson, Fekitoa, Young Cons: Umaga 5 Pens: Umaga 2|
Marcus Smith's last-gasp score capped a marvellous individual display and snatched the points from Wasps for 14-man Harlequins to boost their Premiership top-four hopes.
Quins led 24-22 at half-time but Mike Brown then saw red for a boot to the face of Wasps hooker Tommy Taylor.
Wasps looked like they would edge it, leading 46-41 with seconds to play.
But Smith sneaked down the short-side and then converted the extras coolly to deliver a precious win.
The victory could prove priceless for Quins, as it took full advantage of Northampton's defeat by Gloucester on Saturday to give them a nine-point buffer with the try-scoring bonus point.
Brown's sending off could yet have repercussions for him at the disciplinary panel, as he will likely be cited and face a hearing - and a ban could end his Quins career before his move to Newcastle this off-season.
In a game which went beyond two hours, and had almost everything you could envisage, two players - Smith and Dan Robson for Wasps - had their fingerprints all over the stellar moments.
Smith, who scored twice himself, showed creativity, sparkle and vision throughout.
His finest moments were a perfectly weighted kick into backfield space for Joe Marchant's score as well as perfect spiral passes for James Lang and Alex Dombrandt to cross.
Robson sniped and prompted for Wasps, who got a losing and try bonus point, and he did not deserve to finish on the losing side having created tries with his vision for Josh Bassett and the break to set-up Paolo Odogwu's score.
Harlequins assistant coach Adam Jones:
On Marcus Smith: "He's a great goal-kicker, his line kicking is outstanding and his game management is outstanding.
"He's got to be on the England tour. He's got to be the future. He's a young kid but is growing all the time.
"He was chatted about with the Lions squad, so (Lions coach) Warren Gatland has obviously seen something special in him as well.
"It's a pleasure having an outside-half like that. I've got to be honest, if he was Welsh he would have 50 caps by now. Hopefully he gets picked in the summer and I'm sure he'll do a grand job."
On Mike Brown's red card: "In those situations when you're being held in it can look a lot worse than it was.
"Let's wait until next week and see what happens. He's gutted. Hopefully common sense prevails."
Wasps head coach Lee Blackett:
"You can't come to the Stoop and score 46 points and lose the game.
"I want to be sat here being really positive about the things that have gone well, but we can't because we've conceded 48 points to lose a game.
"It wasn't just the last 10 minutes, it was throughout the game. Our defence fell off a cliff."
Harlequins: Brown; Green, Marchant, Northmore, Murley; Smith, Care; Marler, Baldwin, Louw, Symons, Lewies, Lawday, Kenningham, Dombrandt.
Replacements: Gray, Garcia Botta, Collier, Lamb, White, Landajo, Lang, Lasike.
Wasps: Robson; Umaga, Bassett, Fekitoa, Odogwu; Kibrige, Miller; West, Taylor, Brookes, Rowlands, Gaskell, Shields, Young, Willis.
Replacements: Oghre, McIntyre, Toomaga-Allen, Cardall, Morris, Porter, Atkinson, Le Bourgeois.
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