Connacht claimed a record victory over Ulster as they ran in six tries in a superb 44-16 Guinness PRO14 derby win at the Sportsground.
The home supporters in the 7,629-strong crowd were belting out 'Jingle Bells' by the finish, as Ultan Dillane's second-half brace, adding to four other tries, sealed a memorable night for Kieran Keane's men.
The westerners' tails were up following their Challenge Cup double over Brive, and Eoghan Masterson, Bundee Aki and Tiernan O'Halloran all touched down to establish a 20-6 half-time lead over their provincial rivals.
John Cooney, who landed two penalties against his former side, could not inspire Ulster who leaked a fourth try to Dillane while Andrew Warwick and Louis Ludik were both in the sin-bin.
Les Kiss' charges did at least get over the whitewash in the final quarter, with Craig Gilroy and replacement Robert Lyttle the scorers, however further tries from Jarrad Butler and Dillane, who rounded off a terrific intercept effort from deep, underlined Connacht's dominance in a history-making win.
Both sides made a host of personnel changes from last week's European fare, but it was Connacht who reacted much the better with a clinical start in Galway.
Flanker Masterson plunged over from a thunderous second-minute lineout maul after Matt Healy - the four-try hero against Brive last Saturday - had displayed his pace twice in quick succession.
With only seven survivors from last week's bonus-point win over Harlequins and Matthew Dalton (throat infection) a late withdrawal, Ulster looked rather rudderless and passive and fell further behind in the seventh minute.
Aki finished off a year in which he became an Ireland international with a robust try, bursting in under the posts after swatting away Peter Nelson's attempted tackle. Healy and Kieran Marmion, who broke from the side of a ruck and fed the try scorer, were both prominent in the build-up, and Jack Carty converted for 12-0.
Ulster showed signs of improvement with Ludik breaking from a Jacob Stockdale pass. Cooney opened their account with a 23rd-minute penalty, but from a Healy-won restart, the hosts hit back with their third try, O'Halloran slipping past Cooney and showing good feet and strength to reach out for the whitewash.
Cooney and Carty swapped penalties past the half-hour mark, as the 14-point gap remained in place. It would have been more but for Niyi Adeolokun stumbling with the try-line in his sight, as Andrew Trimble and Stockdale recovered to deny the Connacht winger near the right corner.
Carty knocked over his second three-pointer following Warwick's sin-binning for accumulated team penalties, and centre Ludik joined him on the sidelines in the 54th minute for a deliberate knock-on.
Dillane tucked away the bonus point soon after with a powerful drive to the line from the home pack, and fit-again flanker Butler crossed from O'Halloran's long pass on the hour mark. Carty converted both for a 37-6 scoreline.
Gilroy ducked out of two tackles to wriggle free for Ulster's opening try, and although O'Halloran saw yellow after racing back to thwart Johnny McPhillips' run from deep, Connacht ruthlessly turned defence into attack when Eoin Griffin intercepted Paul Marshall's pass and linked with fellow replacement Darragh Leader, who then put the supporting Dillane gleefully diving in under the posts.
Ulster youngster Lyttle's well-taken 79th-minute score from close range could not take the shine off Connacht's pulsating performance as they supplied a much-needed shot in the arm to their PRO14 form.