Cardiff Blues won a Anglo Welsh LV Cup thriller of a match 45-40 in which 12 tries were scored at Cardiff City Stadium on Sunday afternoon.
Incredibly both teams manged to score six tries each but Blues winger Tom James scored four tries of his own.
The match was expected to have a measure of the "dead-rubber" factor as both teams were out of the running for the play offs and were bottom of their pools.
Forwards Luke Hamilton and Macauley Cook joined the forgotten Wales wing James in crossing the Londoners' whitewash in the dead pool tie while Seb Stegmann (2), Ross Chisholm (2), Chris York and Sam Smith replied for Quins.
Ben Blair's kicking proved the difference against youthful opponents, the Blues full-back slotting 15 points on his return after 16 months out with a knee injury.
Flanker York gave Harlequins an early lead and fly-half Rory Clegg landed the first of four conversions before Blair kicked a penalty ahead of Stegmann stealing a loose ball and trotting over.
James finished from close range to reduce the Blues' deficit and the flyer then created an opening for number eight Hamilton to put the hosts ahead for the first time.
The left wing scored his second before half-time and claimed his hat-trick early in the second period after being sent through a gap by the soft hands of Gavin Henson.
Wing Smith and full-back Chisholm raced 60 yards to touch down in the left-hand corner but the Blues regained control through lock Cook and James' fourth try for a big 45-28 advantage.
Injuries left the home team down to 14 men in the closing minutes, which allowed Stegmann and Chisholm to cross for late scores.
Final Score Cardiff Blues 45 (24) Harlequins 40 (14)
Tries: James 4, Hamilton, Cook
Conversions: Blair 6
Tries: York, Stegman 2, Smith, Chisholm 2
Conversions: Clegg 4, Urdapilleta
Cardiff Blues 15 Ben Blair 14 Richard Mustoe 13 Gavin Evans 12 Gavin Henson 11 Tom James 10 Ceri Sweeney 9 Lewis Jones 8 Luke Hamilton 7 Josh Navidi 6 Maama Molitika 5 Macauley Cook 4 Cory Hill 3 Scott Andrews 2 T Rhys Thomas (Capt) 1 John Yapp
16 Ryan Tyrell 17 Nathan Trevett 18 Sam Hobbs 19 Paul Tito 20 Xavier Rush 21 Sion Hopkins 22 Gareth Davies 23 Casey Laulala
Harlequins :15. Ross Chisholm , 14. Seb Stegmann , 13.George Lowe , 12. Tom Casson , 11. Sam Smith , 10. Rory Clegg , 9. Karl Dickson, 8 Tom Guest , 7 Will Skinner (C) , 6 Chris York , 5 Pete Browne, 4 Tomas Vallejos , 3 Tim Fairbrother , 2 Rob Buchanan ,1 Nic Mayhew
Replacements : 16 Darryl Marfo , 17 Mark Lamber , 18 Will Collier , 19 Charlie Matthews , 20 Joe Trayfoot , 21 Richard Bolt , 22 Benjamin Urdapilleta , 23 Ollie Lindsay-Hague