Mounié broke the deadlock for Huddersfield on 12 minutes after prodding in a Christopher Schindler flick-on at the back post to claim his third goal for the club, and his first since the opening weekend at Crystal Palace.
The 23-year-old added a second from another cross two minutes before the half-time whistle, this time directing Schindler’s counterpart Mathias Jørgensen’s head-down past the noticeably low-on-confidence Mat Ryan.
The visitors showed a surprising lack of ambition throughout, which helped Town hold on for a fifth league win of the season, all of those coming on home turf, and a first clean sheet since the 0-0 draw at Burnley back in September.
After heavy snowfall on Friday night, it was a freezing day in West Yorkshire, but not cold enough to keep fans at home as 24,018 spectators watched the first ever top-flight meeting between both sides.
David Wagner named three changes to his team on the back end of Everton’s hopeful resurgence under new manager Sam Allardyce last weekend – Chris Löwe, Jonathan Hogg and Steve Mounié replaced Scott Malone, Danny Williams and Laurent Depoitre.
Huddersfield had to be prepared to stop a familiar face right from the get-go, as flamboyant left winger Izzy Brown was named in Brighton’s eleven for a second week running ahead of club record signing José Izquierdo.
Alterations in Chris Hughton’s starting line-up were expected after the Amex Stadium witnessed a 5-1 mauling at the hands of free-scoring Liverpool last time out, and he delivered.
Marcus Suttner came in for Gaëtan Bong at right-back whilst the only real surprise was that Anthony Knockaert didn’t just make way for Ezequiel Schelotto, but was absent from the whole squad.
Mounié back in the goals
The hosts enjoyed most of the ball in the opening stages as light snow begun to pour over the action, but it was Jonas Lössl who was tested early on and tipped a glancing Glenn Murray header away from danger – the offside flag had gone up but an acrobatic stop nonetheless.
Steve Mounié was enjoying his fifth league start of the season and forced Mat Ryan into a good save on eight saves after firing an unclean volley towards the Australian’s bottom left corner.
Mounié is always a presence at set pieces, and royally made his presence felt in the 12th minute. The first corner of the afternoon, courtesy of Chris Löwe, found its way to the unmarked striker, who couldn’t have wished for an easier goal, at the far post.
Brighton responded well to going behind and were using Pascal Groß as their main creative outlet in the final third, but the resolute Terriers continued to win most 50/50 challenges all over the pitch and looked fairly comfortable as the half-hour mark approached.
Two minutes from the half-time whistle, Steve Mounié pounced again to double Huddersfield Town’s lead.
Aaron Mooy got on the end of a Mat Ryan punched clearance before shimmying past two defenders outside the left side of the box and floating a cross onto the head of Mathias Jørgensen, who nodded the ball down for Mounié to fire home in the middle of the area.
Huddersfield up to 11th
Chris Hughton took action at the break by enforcing a midfield change as Solly March came on for the uninspiring Ezequiel Schelotto, while goalkeeper Ryan stayed on the pitch to train one-on-one with a coach – he could’ve done a lot more to prevent the hosts’ second.
The away side were looking very positive at the start of the second period and two chances eluded them within the first 10 minutes.
Pascal Groß’s fiercely struck goal-bound effort on the edge of the area was blocked well before a clever first touch by Davy Pröpper set himself up nicely, but the same can’t be said about his effort – a half-time which flew high and wide of Jonas Lössl’s goal.
It was then Huddersfield’s turn to apply the pressure in an attempt to grasp a third goal to put the game to bed as the 60-minute mark approached.
Tom Ince’s frustrations in front of goal continued after Mat Ryan somehow stopped his point-blank poke towards goal from a Tommy Smith ball in – the ex-Derby County wide man has had more shots than any other Premier League player without netting this term.
Steve Mounié carried on causing the Brighton back line problems and thought he should’ve had a penalty in the 64th minute. The Beninese striker’s attempted whipped cross hit the arm of Lewis Dunk, but the no. 5 didn’t intend to do so and it would’ve been a harsh call.
The order of play was all Huddersfield as the second half went on and after a few goalmouth scrambles and captain Tommy Smith going very close with a bending effort from the right it was unbelievable how the score line remained at 2-0.
Tomer Hemed entered the field of play to make his 100th Seagulls appearance on 74 minutes at the expense of Izzy Brown, who received a warm standing ovation as he took to the bench.
Tom Ince was fantastic all afternoon and really deserved his first Huddersfield goal, but Ryan seemed to be level to everything he threw at him over the course of the match and made way for Joe Lolley, making his Premier League debut, with five left on the clock.
There was no Brighton spark for the remainder of the match, which meant Huddersfield not only claimed all three points in their first ever top-flight clash, but leapfrogged Chris Hughton’s men in the league table and remain five points above the relegation zone.
The defeat leaves the Seagulls in 13th place and just four points in safety after West Ham United's shock 1-0 triumph over Chelsea earlier on today, and face the daunting task of a trip to Tottenham Hotspur on Wednesday night.
David Wagner and co. don't exactly have it easy either this week with Antonio Conte's reigning champions coming to town - it's likely Eden Hazard and Álvaro Morata will prove to be a much tougher test.