Harlequins and Gloucester scored five tries each in an extremely entertaining 39-39 draw at Twickenham on Sunday.
The Cherry and Whites took an early 7-0 lead through Jeremy Thrush's try before Nick Evans' penalty and Marland Yarde's touchdown moved Quins ahead.
However, David Humphreys' men were clinical when the opportunities arose and they went 17-8 in front via James Hook's score and the accurate boot of Greig Laidlaw.
Danny Care went over before the break to reduce the arrears but a topsy-turvy encounter had plenty more twists in the second period.
The teams traded tries in the third quarter as Nick Easter and Ross Chisholm touched down for the hosts and Henry Trinder crossed the whitewash twice for Gloucester.
Although the visitors appeared to have wrestled control through Rob Cook's try and Laidlaw's effort off the tee, Evans' penalty and Chisholm's touchdown meant the sides had to settle for three points each.
Harlequins' sojourn to Twickenham around Christmas time has become an annual event, but the West Country outfit set out to spoil the day for Conor O'Shea's side.
Just six minutes had elapsed when Gloucester took the lead through a brilliant piece of skill from second-row Thrush.
After Charlie Sharples had broken down the right wing, the New Zealander kicked through and touched down ahead of Jack Clifford as Humphreys' team took the lead.
It was the type of score that was indicative of the first half. Although the hosts had most of the possession, the Cherry and Whites were always a threat off turnover ball.
Quins did eventually get the scores their endeavour deserved as Evans' penalty and Yarde's try gave them an 8-7 advantage, but they were up against a side who snaffled their chances.
Laidlaw kicked a three-pointer before superb work from Matt Kvesic sent Hook free and the stand-off went over unopposed.
The London-based outfit did hit back just before the break through Care's close-range effort, but Trinder's intercept eight minutes into the second period gave Gloucester a nine-point buffer.
It was proving to be a remarkable match with the visitors capitalising on Harlequins' over-exuberance. However, the hosts' expansive nature did pay off with two tries in quick succession.
The first came through Easter, who benefited from Evans' and Care's excellence, before Jamie Roberts and Mike Brown combined to send Chisholm across the whitewash for another outstandingly worked move.
The scene was now set for O'Shea's team to garner control of proceedings but mistakes once again became prevalent.
Care's pass was intercepted by Trinder to level matters before Laidlaw moved the Cherry and Whites in front once again.
Cook then scampered over the line and at 39-29 it looked as though it was game over, but Quins displayed their resilience to come back into the encounter.
Evans was on target from the tee and Chisholm crossed for the second time as both teams had to accept a share of the spoils.
Tries: Yarde, Care, Easter, Chisholm 2
Cons: Evans 4
Pens: Evans 2
Tries: Thrush, Hook, Trinder 2, Cook
Cons: Laidlaw 4
Pens: Laidlaw 2
Yellow Card: Hibbard
Harlequins: 15 Mike Brown, 14 Marland Yarde, 13 George Lowe, 12 Jamie Roberts, 11 Tim Visser, 10 Nick Evans, 9 Danny Care (c), 8 Nick Easter, 7 Jack Clifford, 6 Chris Robshaw, 5 Charlie Matthews, 4 James Horwill, 3 Will Collier, 2 Dave Ward, 1 Joe Marler
Replacements: 16 Rob Buchanan, 17 Mark Lambert, 18 Kyle Sinckler, 19 George Merrick, 20 Luke Wallace, 21 Karl Dickson, 22 Ben Botica, 23 Ross Chisholm
Gloucester: 15 Rob Cook, 14 Charlie Sharples, 13 Henry Trinder, 12 Billy Twelvetrees, 11 Jonny May, 10 James Hook, 9 Greig Laidlaw (c), 8 Ross Moriarty, 7 Matt Kvesic, 6 Sione Kalamafoni, 5 Mariano Galarza, 4 Jeremy Thrush, 3 John Afoa, 2 Richard Hibbard, 1 Dan Murphy
Replacements: 16 Darren Dawidiuk, 17 Dan Murphy, 18 Nicky Thomas, 19 Tom Savage, 20 Jacob Rowan, 21 Willi Heinz, 22 Billy Burns, 23 Henry Trinder
Referee: Wayne Barnes
Assistant Referees: Gregory Garner, Wayne Falla
TMO: Graham Hughes