Huddersfield opened the Super League season with a commanding 24-8 victory over Wigan at the DW Stadium.
The fixture was brought forward a week to enable the Warriors to fly down under to prepare for their World Club Challenge clash with Sydney Roosters, but they will travel under a cloud after a disappointing start to their domestic title defence.
The defeat was compounded by injuries to England internationals Sean O'Loughlin and Michaell McIlorum while debutant full-back Matty Bowen, the man signed to replace Sam Tomkins, is facing a possible ban after being put on report for a high and late tackle on his opposite number Scott Grix.
Wigan's misery was in sharp contrast to the joy experienced by the Giants, who did the double over Wigan on their way to topping the table in 2013 and, on this form, could be a good bet to go all the way to the Grand Final.
Inevitably, Huddersfield skipper Danny Brough, the 2013 Man of Steel, was at the heart of his side's impressive display, despite an off day with the boot.
Already without last year's leading try-scorer Josh Charnley, the champions suffered another body blow before kick-off, when skipper O'Loughlin pulled out with a thigh injury sustained in training which forced coach Shaun Wane into a hasty reshuffle.
McIlorum started on the bench after apparently recovering from a hamstring injury but he did not enter the action until the 50th minute and lasted only 16 minutes before coming off. Huddersfield, who gave debuts to former London forwards Chris Bailey and Antonio Kaufusi, also had their setbacks.
They were forced to overcome the loss of second rower Larne Patrick, who fell awkwardly a minute before half-time and was carried off on a stretcher with a knee injury, and hooker Shaun Lunt, who hobbled off midway through the second half.
Huddersfield were already well in control by then, having dominated the first half with a combination of enterprising attacking play and smothering defence.
Second rower Brett Ferres, one of England's big successes of the World Cup, got the first try of the season, touching down Aaron Murphy's delicate kick just four minutes in after first releasing the Giants winger with a deft pass.
McGillvary grabbed his first try on 16 minutes, latching onto Shaun Lunt's inch-perfect grubber kick, to double Huddersfield's lead and the brilliant Brough ensured his side stayed in command.He pulled off two tremendous tackles on centre Darrell Goulding when Wigan threatened to break free of the shackles and produced a 40-20 kick to turn defence into attack.
The Scotland skipper almost scythed through for a solo try but the pressure told on 29 minutes when Leroy Cudjoe's long pass gave McGillvary the space to go over for his second score. Brough blotted his copybook by failing with all three conversion attempts, the first of which rebounded off an upright, and he was also off target with a drop-goal attempt on the stroke of half-time.
The Giants captain then fluffed a glorious tryscoring opportunity two minutes into the second half, putting down a pass from Joe Wardle with the line beckoning, and the misses suddenly began to look costly as Wigan staged a brief fightback.
Left winger Iain Thornley produced a clinical finish to get the Warriors on the scoreboard two minutes later and a fumble by McGillvary enabled Wigan to maintain the pressure, with Bowen getting teenage winger Joe Burgess at the other corner.
The Giants had spent most of the second half on defence but, once they got their hands on the ball, they instantly looked dangerous and increased their lead, with McGillvary squeezing over at the corner to complete his hat-trick.