Few positives on a disappointing day
At times in the first half, you felt Huddersfield were there for the taking but Albion didn't take advantage or capitalise.
Both sides went into the game in indifferent form - the Terriers had lost four in a row, while Brighton had picked up just two points from four games.
But the longer the game went on, the more dominant Huddersfield became and it was only a couple of sharp saves from Mathew Ryan in the second half which kept the scoreline down.
There were few, if any, positives to take from the game for Brighton. It's one to chalk down as a bad day at the office but they can't afford too many more performances like this.
A trip to Wembley on Wednesday to take on a Tottenham side who won 5-1 today is a daunting prospect before back-to-back home games with Burnley and Watford, which could almost be classed as must-win.
For the fourth time in five games, Brighton conceded from a corner and they need to quickly buck that trend.
Stoke's second in the 2-2 draw at the Amex came from a set-piece and Manchester United then scored the only goal at Old Trafford when Albion only half-cleared a corner.
Emre Can was unmarked to head Liverpool into the lead in their 5-1 victory last week and Huddersfield's early goal would again have disappointed Seagulls boss Chris Hughton.
Christopher Schindler flicked on a corner and Steve Mounie was left unmarked to chest the ball into an empty net from a couple of yards at the back post.
Huddersfield's second also came following a corner. Chris Lowe's ball in was cleared out to Aaron Mooy, who crossed the ball back in and Mounie nodded home after Mathias Zanka headed the ball back into the danger area - although Seagulls keeper Mathew Ryan will be disappointed not to have kept it out.
Albion have slipped to 13th with the defeat. They will need to improve their defending from set-pieces to end a five-game winless run in the Premier League.
We've (not) got Knockaert
Albion's talismanic winger was not in a matchday squad for the first time this season.
Knockaert was pictured walking into the John Smith's Stadium pre-match and was also mingling with the Seagulls players as they walked off the pitch following their warm-up, high-fiving Pascal Gross and Tomer Hemed.
A ankle injury sustained in the pre-season training camp in Austria meant Knockaert began the opening two games of the season on the bench, before starting his first match of the campaign in the EFL Cup against Barnet.
The Championship player of the season has not been quite as influential as in the Premier League this year but had been shown signs of hitting top form in the past few weeks.
Asked about Knockaert's absence from the matchday squad afterwards, Albion boss Chris Hughton said it was just a selection decision to leave the winger out.
All eyes on you
England manager Gareth Southgate was an interested spectator - no doubt having a look at Brighton defender Lewis Dunk, who has impressed with his performances so far this season.
Dunk had been tipped for a call-up to the friendlies with Germany and Brazil last month but was over-looked by Southgate with Liverpool youngster Joe Gomez involved with Englanf for the first time.
Southgate had pen and paper in hand to make sure he kept track of the action and his eyes were firmly on Dunk - on and off the ball - during the first half.
Six other English players started the game - Dale Stephens, Izzy Brown, Glenn Murray, Tommy Smith, Jonathan Hogg and Tom Ince - while Solly March was also introduced as a half-time substiutute.
England have two friendly matches in March against the Netherlands and Italy,before the provisional World Cup squad will be announced at the end of the season.
We meet again
Huddersfield and Brighton battled it out at the top of the Championship last season. The Terriers pushed Newcastle and Albion all the way for the automatic promotion places, before going up through the play-offs.
Brighton beat Huddersfield 1-0 at the Amex last season, while the Terriers were outstanding in a 3-1 home victory over the Seagulls last year.
Unfortunately for Albion, it was almost a repeat of last season - with Huddersfield dominant and Albion below-par at the John Smith's Stadium.
Today's match also saw Izzy Brown return to Huddersfield. The 20-year-old played a key role in helping the Terriers gain promotion on loan from Chelsea in the second half of last season.
Brown joined the Seagulls on a season-long loan from Chelsea this summer and started his fourth Premier League game of the season this afternoon. He struggled to get on the ball much and afterwards admitted, despite receiving a warm reception from the home fans, it had been a disappointing afternoon.
No one said it would be easy
Chris Hughton said in the summer that Albion could go through spells of four, five or six games without picking up many points as that's the nature of the Premier League - and that's proved to be the case in the last five games.
Albion have picked up just two points from those matches but this was easily the most disappointing defeat of the season, especially on the back of three strong away performances.
Brighton recorded back-to-back away wins at West Ham and Swansea, before they should have returned home with a point from their 1-0 defeat at Manchester United.
Today, Albion again conceded poor goals and didn't look like scoring at the other end. One Huddersfield reporter afterwards said it was up there with the best the Terriers have played this season but it will again be a long drive home for the Brighton faithful.