Match ends, Manchester United 2, Brighton and Hove Albion 1.
Ole Gunnar Solskjaer became the first Manchester United manager to win his first six league games in charge as his side held on to beat Brighton.
It was United's seventh straight win since the Norwegian took over at Old Trafford on an interim basis a month ago and they are now just three points off fourth-placed Chelsea, who lost to Arsenal in Saturday's late kick-off.
Paul Pogba put United in front after winning and then converting a penalty in the 27th minute.
Marcus Rashford doubled the lead just before half-time with a beautiful solo goal on his 150th appearance for the club.
Pascal Gross halved the deficit for the visitors when he scored in off the bar with just over 20 minutes remaining.
Brighton improved in the second half but their wretched away record continued as they fell to a fifth defeat in their last eight Premier League games.
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United's winning streak continues
The last time these sides met was in August, when United's season under Jose Mourinho began unravelling with a 3-2 defeat.
But United's first-half performance at Old Trafford on Saturday was worlds apart from that game last summer.
Solskjaer almost had the luxury of naming an unchanged line-up for back-to-back league games for the first time since December 2017, but Luke Shaw fell ill in the warm-up and Diogo Dalot took his place.
United put Brighton under relentless pressure from the off and deservedly took the lead.
Nemanja Matic's cross-field pass found Pogba, whose first touch took him past Gaetan Bong and the defender then clumsily nudged him over.
The Frenchman's stuttering penalty run-up has not completely disappeared, but this was nowhere near as long as his 26-step effort against Everton back in October and he slotted his shot past David Button.
Rashford's recent goalscoring form continued as he got his ninth of the season and his fifth under Solskjaer.
The England striker was played in by Dalot, sent Gross the wrong way and then bent his shot into the top corner.
Rashford was excellent for the first hour, spraying passes about with confidence and whipping in a stunning cross for Jesse Lingard, who prodded wide when he really should have scored.
They should have had more to show from their 20 attempts, but only five were on target, with Pogba and Anthony Martial guilty of missing chances.
United eased off in the final 20 minutes, lacking sharpness and became sloppy as they missed out on a fourth clean sheet in a row.
"Today we were tested," said Solskjaer. "I didn't think we played the game out as we should have. That's perhaps the next challenge for the boys.
"Sometimes you make it hard work. I thought we played some greats stuff at times. At the start of the second half we could have finished the game with great chances.
"The last 20 minutes we were in trouble. You can't always play fantasy football. At times we did and it's a great three points."
More away day blues for Brighton
Chris Hughton's side have won eight points away from the Amex Stadium this season and have just four away wins since joining the Premier League last season.
They particularly struggle against the top sides Following last week's defeat by Liverpool and Saturday's loss at Old Trafford, they have now lost all nine of their Premier League away games against 'big six' sides by an aggregate score of 19-2.
The first half against United proved damaging, as they rarely threatened and struggled to cope with the hosts' forward line.
A double change on the hour mark with the introductions of Florin Andone and Anthony Knockaert provided the attacking impetus the Seagulls needed.
Davy Propper did well to create Gross' goal, flicking a pass with the outside of his boot over the head of Victor Lindelof to the German, who chested it down and fired his shot off the bar and in.
Brighton finished the stronger, their attacks and crosses sparking panic in the United team, but it came too late.
"The biggest disappointment is the goals we conceded," said Hughton. "I thought we very much gave them a game.
"We will need lots of that come the end of the season but I thought there was a chance for us today.
"We needed a bit more quality in the final third and in general."
Asked about bringing players in January, he added: "You can never say never but I don't think it will be the case. Possibly one or two will be going out on loan."
Man of the match - Marcus Rashford
On Rashford's form, Solskjaer said: "What a finish. That was the first thing I said to him when I met him. He had missed some chances and I said 'no problem, you'll be all right, just settle down a little bit'."
Pogba equals best goals return - the best stats
- Solskjaer is just the third manager in Premier League history to win his first six games in charge of a club, after Carlo Ancelotti with Chelsea and Pep Guardiola with Manchester City
- United have won more penalties (seven) while Brighton have conceded more (also seven) than any other Premier League side this season
- Pogba's goal was his eighth in the Premier League this season, equalling his best return in a single season in the top five European leagues (also eight with Juventus in 2014-15 and 2015-16).
- Rashford has now scored in his last four Premier League games. Only Anthony Martial (five) has had a better such run in the competition this season
United travel to the Emirates Stadium to face Arsenal in the FA Cup fourth round on Friday (19:55 GMT), a game that is live on BBC One. They then host Burnley in the league on 29 January.
Brighton are also in cup action and host Championship side West Brom on Saturday (15:00 GMT). The Seagulls then travel to Premier League strugglers Fulham on 29 January.
- 1De Gea
- 14LingardSubstituted forMataat 75'minutes
- 10RashfordBooked at 90minsSubstituted forDarmianat 90+4'minutes
- 11MartialSubstituted forLukakuat 83'minutes
- 20MarchSubstituted forKnockaertat 61'minutes
- 13GroßSubstituted forKayalat 82'minutes
- 17MurraySubstituted forAndoneat 60'minutes
- Paul Tierney
- Shots on Target
Second Half ends, Manchester United 2, Brighton and Hove Albion 1.
Foul by Ashley Young (Manchester United).
Florin Andone (Brighton and Hove Albion) wins a free kick on the left wing.
Substitution, Manchester United. Matteo Darmian replaces Marcus Rashford.
Marcus Rashford (Manchester United) is shown the yellow card for a bad foul.
Foul by Marcus Rashford (Manchester United).
Martín Montoya (Brighton and Hove Albion) wins a free kick on the right wing.
Corner, Brighton and Hove Albion. Conceded by Victor Lindelöf.
Ander Herrera (Manchester United) wins a free kick in the defensive half.
Foul by Gaëtan Bong (Brighton and Hove Albion).
Attempt missed. Paul Pogba (Manchester United) right footed shot from outside the box is close, but misses to the left. Assisted by Diogo Dalot.
Delay over. They are ready to continue.
Delay in match Marcus Rashford (Manchester United) because of an injury.
Corner, Brighton and Hove Albion. Conceded by David De Gea.
Foul by Paul Pogba (Manchester United).
Anthony Knockaert (Brighton and Hove Albion) wins a free kick on the right wing.
Substitution, Manchester United. Romelu Lukaku replaces Anthony Martial.
Substitution, Brighton and Hove Albion. Beram Kayal replaces Pascal Groß.
Attempt saved. Marcus Rashford (Manchester United) right footed shot from long range on the left is saved in the bottom right corner.