It was a game worthy of the final, let alone round 19, as both teams set out to play an attacking brand of rugby which did the tournament proud.
Gloucester produced possibly their best rugby of the season, certainly from an attacking perspective, and they had to against an opponent who aren't Aviva Premier champions for nothing.
Nigel Davies' side threw the kitchen sink at Harlequins in the first half, yet only had three points to show for their efforts.
On the other hand, the visitors expertly exploited the two main chances that came their way in the first half, Rob Buchanan and Sam Smith both touching down.
Smith's try, in particular, would have broken both sides as Gloucester had just earned their first points of the evening, only to immediately concede.
However, time and time again this season, the talk has been of Gloucester's resilience and it was to the fore again this evening.
Jonny May crossed early in the second half to give both team and crowd self belief and, from that moment on, it was a prize fight with both teams landing blows but unable to knock their opponent out.
Finally, Gloucester, backed by a sensationally vocal crowd, blasted their way over from close range with ten minutes left to play to earn the lead before digging deep to keep Quins at bay in the final few minutes.
Referee JP Doyle blew for time, Kingsholm erupted in joy and relief and Gloucester were left to reflect on another exciting chapter in their history.
The win keeps them in fifth place, but Gloucester are now level on points with Northampton and within two of Quins.
The season is very much alive and there's the small matter of an Amlin Challenge Cup quarter final against Biarritz on Thursday evening….
Both teams started brightly, showing ambition from the very first whistle, and the Kingsholm crowd was quick to voice its appreciation.
The game was fairly physical as well as being open, and Gloucester were dealt a blow when they lost their skipper Jim Hamilton after only five minutes.
Quins' first attack with ball in hand was a dangerous one. Ross Chisholm made good metres down the right, but George Lowe lost the ball in contact deep in the home 22.
Gloucester were being penalised for early engagement at the scrum, though, and it cost them dear. A quick tap just a few metres out allowed hooker Rob Buchanan to muscle his way over for a 5-0 lead.
The response was impressive as Gloucester moved the ball at pace to stretch the visiting defence, but no immediate score was forthcoming despite Twelvetrees and Sharples combining brilliantly down the right.
This was Gloucester at their scintillating best and, to be fair, the Quins defence was superb although they did seem to be living on the edge.
Finally, referee JP Doyle awarded a penalty Gloucester's way as Quins failed to clear the tackle area and Freddie Burns slotted the penalty.
Gloucester were then caught cold straight from the restart. Nick Evans spotted a flat defensive line in front of him, and measured his chip perfectly for Sam Smith to gather and score under the posts. Evans converted for a 12-3 lead after 23 minutes.
It was a real kick in the teeth for the Cherry and Whites who had played some sensational rugby to earn their three points only to concede a try immediately afterwards.
Gloucester's reaction was to continue to play the game with ball in hand, and a superb counter looked set to result in a score for Rob Cook but the full back lost control of the ball as he crossed the Quins 22 when seemingly clear.
The frenetic pace showed no signs of letting up, and Burns had a chance to add a second penalty but his kick held up in the wind and drifted wide.
A pulsating half drew to a close with the visitors in the ascendant by 12 points to 3, but the Kingsholm faithful were shaking their heads in disbelief at the scoreline.
Gloucester had stretched the Aviva Premiership champions to the very limit, and quite how they only had three points to this point was anyone's guess.
However, it's a game of taking chances and Harlequins had taken their opportunity brilliantly whilst also looking dangerous on other occasions.
If the second half lived up to the first, this one would remain long in the memory.
The start was sensational. Mike Brown almost broke clear but Freddie Burns intercepted his offload and Gloucester countered in style.
Charlie Sharples showed amazing pace and his inside offload found Billy Twelvetrees who almost made the line. Gloucester stayed patient, moved it left and Jonny May stepped the final man to score. Burns added a superb touchline conversion to narrow the gap to 12-10.
The visitors were stung and unleashed a prolonged attack, maintaining possession through multiple phases, but Gloucester just kept their line intact despite being under severe pressure.
The Kingsholm crowd was rapidly losing patience with the refereeing decisions - Danny Care actually fed a scrum from the wrong side before moving to the other side after a reset - and boos erupted when yet another decision against Gloucester allowed Evans to extend the lead to 15-10.
Turning down possible kicks to goal, Gloucester duly laid siege to the Quins line and the visitors had to resort to desperate measures to keep Nigel Davies' side at bay, Joe Gray eventually being yellow carded.
Gloucester opted to scrum and, although the eight man shove was not quite enough, the combination of Kalamafoni and then Qera powered over, the Fijian claiming the try. Burns' conversion gave Gloucester the lead at 17-15.
With ten minutes left to play, there was ample time for Quins to work their way into penalty or drop goal range, But Gloucester's discipline was exemplary in the face of some innovative attacking.
Every man in a Cherry and White shirt, made his tackles and Quins just couldn't breach the line as Gloucester held out to take the points.
|Gloucester Rugby Score Card|
|Harlequins Score Card|