Mason Greenwood's fine header lifted Manchester United to a 2-1 win over Brighton to strengthen the hosts' grip on second place.
Ole Gunnar Solskjaer's side are now 14 points behind fierce rivals Manchester City and four ahead of third-placed Leicester. Brighton remain in 16th and six points off the relegation zone.
United began brightly under the lights and Greenwood cracked a close-range effort off the woodwork in the eighth minute. But five minutes later and Brighton took a surprise lead.
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An excellent cross from the right flank by Neal Maupay found his strike partner Welbeck, who nodded his point-blank header into the feet of Dean Henderson before heading in the rebound against his old club.
Danny Welbeck (2R) celebrates
Image credit: Getty Images
The visitors, sensing United's vulnerability at the back, almost extended their lead in the 18th minute through Lewis Dunk, but the defender's header was tipped onto the crossbar by Henderson.
United were struggling to deal with Brighton's 3-4-1-2 shape and looked progressively disheartened as the half went on. United did not fashion out a shot on target in a drab first-half display, encapsulated by Paul Pogba's sidefooted effort which flew wide.
A minute before half-time Jakub Moder saw his first-time shot deflect off Rashford and roll inches wide of Henderson's left post.
Rashford's shot straight at Robert Sanchez in the 52nd minute was United's first on target. His second ten minutes later would pull United level. Bruno Fernandes laid it off to his left where Rashford was there in space to place his simple finish into the bottom corner.
United continued to improve, but Welbeck almost put Brighton in front twenty minutes from time when he stabbed a close-range effort at the near post agonisingly wide. There were appeals for a penalty as the 30-year-old protested he was pushed by Harry Maguire, but referee Mike Dean waved play on after consulting with VAR official Peter Bankes.
Greenwood, who was United's most potent threat all evening, scored the winner in the 83rd minute by steering Pogba's scuffed volley into the net with a smart diving header.
TALKING POINT - Man Utd show backbone
United were poor in the first half, but they came to life in the second and twice found a way to break down Brighton's stingy backline. Once again Brighton showed their ability to impress and fall short at the same time.
For United the Premier League mission is to retain second place and this hard-fought victory gives them positive momentum heading into their Europa League quarter-final first leg tie at Granada on Thursday night.
MAN OF THE MATCH - Mason Greenwood
Greenwood stepped up and delivered the killer blow on an evening his more experienced teammates did not look like doing so.
The highly-rated forward came closest to scoring for United in the first half when they were collectively not at their best, and the 19-year-old's fantastic improvisation to convert the winner will have undoubtedly delighted Solskjaer.
Manchester United: Henderson (5), Shaw (6), Wan-Bissaka (5), Lindelof (6), Maguire (6), Fred (6), Pogba (7), Fernandes (6), Greenwood (8), Rashford (7), Cavani (5)
Subs: James (6), Van de Beek (N/A), McTominay (N/A)
Brighton: Sanchez (6), White (6), Dunk (6), Veltman (6), Bissouma (6), Lallana (6), Moder (6), Gross (6), Trossard (6), Welbeck (7), Maupay (6)
Subs: Mac Allister (5), Jahanbakhsh (N/A), Zeqiri (N/A)
8' - Fernandes plays it short to Rashford before he gives it backThe clearance comes out to Greenwood.... and he SMASHES IT AGAINST THE POST! That was a fine effort from the 19-year-old.
13' - GOAL!!! Welbeck scores against his old club!! Maupay's excellent cross into the box from the right is nodded from point-blank range on goal by the ex-United striker. Henderson saves it with his feet before Welbeck quickly nods in the rebound! Brighton lead!
18' - OFF THE BAR! Brighton have a free-kick on the left-hand side because of a Wan-Bissaka handball. Gross' cross is headed on goal by Dunk and it is fingertipped onto the crossbar by Henderson! The corner swung in by Gross is punched clear by Henderson under heavy pressure.
62' - GOAL!!! Rashford equalises!! Fernandes lays the ball off to Rashford on his left and he calmly slots his finish into the far corner. United back on level terms! It is Rashford's first goal in seven games for United.
70' - JUST WIDE!!! VAR... NO PENALTY! Welbeck fires just wide from close-range and there's strong appeals for a penalty as there is contact between him and Maguire. Referee Mike Dean is going to consult the VAR monitor. A penalty would be harsh... Dean did not feel there was enough there to merit a spot-kick. Play on.
83' - GOAL!! Greenwood puts United in front late on! Fernandes' cross is scuffed on the volley by Pogba, but it veers into the path of Greenwood, who shows a poacher's instinct to direct a diving header into the net. United in front!
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