Match ends, Brighton and Hove Albion 0, Sheffield United 1.
Oliver McBurnie scored the winner as Sheffield United beat Brighton to move up to fifth in the Premier League, with boss Chris Wilder revealing he "had a hunch" it was time for his record signing to return to the side.
Scotland international McBurnie latched on to goalkeeper Dean Henderson's long ball to smash home the winner in the first half.
It was his third Premier League goal in a season that has warranted only seven starts since the 23-year-old's £20m switch from Swansea in the summer.
Wilder scouted McBurnie while he was playing under Brighton manager Graham Potter for the Swans last term and backed the forward to deliver against his old boss.
"We had a hunch that this would be a good day for Oli," said Wilder.
"We just felt this was the right time, against his old manager and the way they set up. It was a great goal in a tight game."
McBurnie's effort earned the Blades a third successive top-flight win for the first time since 1993.
United could have been out of sight, twice having goals ruled out by the Video Assistant Referee and watching David McGoldrick hit the side-netting after rounding Brighton goalkeeper Mat Ryan.
Brighton's best move of the match resulted in Neal Maupay tapping in from close range, but Martin Montoya was offside earlier in the move.
The Blades go fifth for now, with Tottenham and Manchester United both still to play.
- Brighton v Sheffield United as it happened
- Reaction to Saturday's Premier League action
- World Cup winner Peters dies aged 76
McBurnie rewards Wilder switch
McBurnie netted 24 times in the Championship last season but has found goals and starts hard to come by so far in the top flight.
Lys Mousset has been the man leading the line for Wilder's side but the boss trusted McBurnie on Saturday and was repaid inside 23 minutes.
McBurnie did superbly to outmuscle Brighton centre backs Adam Webster and Lewis Dunk to go through on goal and fire in off the post.
"He's been knocking on the door during the week which is something that we always look at - away from the light Monday to Friday," added Wilder.
The striker praised Wilder's gameplan afterwards while insisting he had to "put myself in the gaffer's thoughts".
He certainly did that with a hard-working performance before being replaced by Mousset just after the hour-mark.
"I know Oli's quality and I know he's capable of scoring. It was nice for him but not nice for us," said Brighton boss Potter.
"I wish him well in the rest of his career because he's a good lad and was great for a year at Swansea."
Wilder wins battle of homegrown bosses
In a battle of two emerging English managers at the Amex, it was Sheffield United's Wilder who came out on top.
The Blades have been superb since returning to the Premier League but few would have banked on them occupying such a lofty position at Christmas.
Potter and Wilder have met before, in the Championship last season when on both occasions the former Swansea manager was victorious.
But Wilder's outfit headed into this one unbeaten away from home this term and took the game to the hosts early on when John Egan bundled in from a corner.
That was ruled out by VAR for handball, as was Jack O'Connell's effort in the second half for offside, as Wilder, who BBC Sport columnist Charlie Webster wrote this week is "making having an English manager look sexy and attractive", got the better of the tactical battle with his opposite number.
Wilder is pragmatic in his approach and his side were happy to sit in and soak up a spell of Brighton pressure late on, while looking dangerous on the break.
Forward McGoldrick dribbled round the goalkeeper only to miss an open goal as the visitors failed to give themselves a more comfortable finish.
Meanwhile, Seagulls chiefs have been so impressed with Potter's start to life at the club they have already offered him a two-year extension on the four-year deal he signed when taking the job in May - seeing the 44-year-old through to 2025.
But after climbing into the top half of the table at the beginning of November, Brighton have won just once in seven games since in the Premier League.
That leaves them on 20 points after 18 games, one fewer than under Chris Hughton at this stage last term.
Man of the match - Oliver McBurnie (Sheffield United)
'We have structure, organisation and desire'
Sheffield United boss Chris Wilder speaking to Match of the Day: "We weren't at our best with the ball but we have a structure, organisation and a desire to keep the ball out of the net. We had to show all those qualities this afternoon.
"We did a job on them, should have had more possession, but we had the better chances on the counter attack and we're delighted to keep the away run going. The next two are Manchester City and Liverpool!
"We kept our shape well and were really disciplined. It's a big three points for us. You always want to get off to a good start.
"It's the Premier League, every team you come across are good and have qualities but we have some qualities as well and we've worked very hard."
Brighton boss Graham Potter speaking to Match of the Day: "We weren't good, Sheffield United did what they did well. First half they were better than us and deservedly it was 1-0.
"It wasn't a game of many chances and we put a lot into it, but not enough. It was a disappointing day for us.
"We didn't play well today. They made it difficult for us and we weren't as good as we like to be. We can look at ourselves and learn from the game, we can do better.
"We had the change the dynamic of the game at 1-0 down. Second half it was better in terms of pressure but not enough in terms of chances.
"You get set-backs in this competition, but we have to get ourselves ready for another tough match."
The stats - Blades continue away run
- Sheffield United have become only the second newly-promoted side in English top-flight history to go unbeaten in their opening nine away league games of a season, after Burnley in 1947-48 (10).
- Brighton have never won a Premier League home game in which they have conceded the first goal. This is the most a team has conceded first at home in the competition without ever coming from behind to win.
- Since the start of last season, no side in the top four tiers of English football have kept more league clean sheets (excluding play-offs) than Sheffield United (28 - level with Leeds United).
- Sheffield United have won three consecutive top-flight matches for the first time since they won four in succession under Dave Bassett between May and August 1993.
- Sheffield United have won each of their last three league meetings with Brighton, their best such run against them since October 1960 (four in a row).
- Sheffield United striker Oliver McBurnie scored his first away goal in the Premier League in what was his 16th appearance on the road in the competition.
Both are back at it on Boxing Day, with Brighton travelling to Tottenham in the 12:30 GMT kick-off and Sheffield United welcoming Watford at 15:00.
- 22MontoyaSubstituted forBissoumaat 56'minutesBooked at 87mins
- 13GroßSubstituted forMurrayat 45'minutes
- 11TrossardSubstituted forConnollyat 45'minutes
- 6BashamBooked at 83mins
- 16NorwoodSubstituted forBesicat 82'minutes
- 8FreemanSubstituted forOsbornat 53'minutes
- 3StevensBooked at 75mins
- 9McBurnieSubstituted forMoussetat 63'minutes
- 17McGoldrickBooked at 85mins
- Robert Jones
- Shots on Target
Second Half ends, Brighton and Hove Albion 0, Sheffield United 1.
Offside, Sheffield United. David McGoldrick tries a through ball, but Lys Mousset is caught offside.
Attempt missed. Adam Webster (Brighton and Hove Albion) header from the centre of the box is high and wide to the left following a corner.
Corner, Brighton and Hove Albion. Conceded by John Egan.
Attempt blocked. Aaron Connolly (Brighton and Hove Albion) right footed shot from outside the box is blocked.
Foul by Glenn Murray (Brighton and Hove Albion).
George Baldock (Sheffield United) wins a free kick in the defensive half.
Foul by Glenn Murray (Brighton and Hove Albion).
Chris Basham (Sheffield United) wins a free kick on the right wing.
Yves Bissouma (Brighton and Hove Albion) is shown the yellow card.
Yves Bissouma (Brighton and Hove Albion) has gone down, but the referee deems it simulation.
David McGoldrick (Sheffield United) is shown the yellow card for a bad foul.
Aaron Mooy (Brighton and Hove Albion) wins a free kick in the defensive half.
Foul by David McGoldrick (Sheffield United).
Attempt missed. David McGoldrick (Sheffield United) right footed shot from the right side of the box is just a bit too high. Assisted by Ben Osborn following a fast break.
Chris Basham (Sheffield United) is shown the yellow card for a bad foul.
Aaron Connolly (Brighton and Hove Albion) wins a free kick on the left wing.
Foul by Chris Basham (Sheffield United).
Substitution, Sheffield United. Muhamed Besic replaces Oliver Norwood.