The win moves the Red Devils up to ninth in the table, the Baggies however remain in the relegation zone and are yet to win this season.
Sportsmail runs the rule over both teams’ performances…
MANCHESTER UNITED (4-2-3-1):
David De Gea – 7
Had one first half save to make, from Grant, and made it well and did likewise from Townsend soon after the restart.
David de Gea made two quality saves to preserve his clean sheet for Manchester United
Aaron Wan-Bissaka – 5
Quiet going forward for once and, when he did, he was badly out of position when Robinson struck the bar for the visitors.
Victor Lindelof – 6
Better display than of late with a couple of well-timed challenges and some good positional decision making.
Harry Maguire – 6
Couple of very good early challenges, one of which set up a counter but caught out for the ‘penalty’ Albion won and were then denied.
Alex Telles – 6
First taste of Premier League football and looked solid defensively. Failed to make an impact going forward, however.
Alex Telles was solid if not spectacular on his Premier League debut at Old Trafford
Nemanja Matic – 6
Steady as usual, chose the simple options and read the game well without making a major mark on proceedings.
Fred – 6
Did a lot of the fetching and carrying that kept United in possession but lacked the vision to make an impact.
Juan Mata – 5
Supposed to add much-needed creativity but despite a couple of neat touches was the obvious man to be first subbed.
Bruno Fernandes – 8
Fortunate to escape a penalty call for a trip on Gallagher and doubly fortunate with United’s own penalty. But still easily their best player.
Marcus Rashford – 6
Quiet first half but close to opening the scoring with an intelligent and skilful shot soon after the restart.
A quiet night for Marcus Rashford, however the 23-year-old went close with a first half effort
Anthony Martial – 5
A threat but two good chances were saved by Johnstone when he would have expected to score.
Edinson Cavani for Mata 63 – 6
Donny van de Beek for Rashford 79 – 6
Scott McTominay for Fred 84
Subs (not used) James, Henderson, Williams, Tuanzebe.
West Brom (5-3-2):
Sam Johnstone – 9
Two goods early saves from Martial and two later from Rashford made it a return to Old Trafford to remember. Unlucky on his penalty “save.”
Sam Johnstone was unlucky to see his penalty save from Bruno Fernandes lead to a retake
Darnell Furlong – 6
Lively couple of minutes where he nearly set up the opener for Townsend then gave away the killer penalty.
Semi Ajayi – 6
Strong performance in the middle of defence but slip almost gifted Rashford a goal.
Kyle Bartley – 7
Bravely took a Maguire shot full in the face, summing up Albion’s defensive spirit. Skipper led by example.
Branislav Ivanovic – 7
Veteran threatened from an early corner and used his experience to make up for an obvious lack of pace against United’s speedsters.
Ivanovic was one of the better performers for West Brom on a frustrating night for the Baggies
Conor Townsend – 5
Was alert for some smart defending that denied Martial a goal-scoring chance then almost opened the scoring after the restart.
Matheus Pereira – 5
Clever pass set up Grant for Albion’s best chance of the first half but did not see enough of the ball to influence much else.
Romaine Sawyers – 7
Grafted in front of his back four and needed to given the amount of possession and pace United had.
Conor Gallagher – 8
Lively display, good delivery from set-pieces and won a penalty – only to have it ruled out by VAR.
Grady Diangana – 5
Covered a lot of ground in support of Grant but ran out of steam and replaced after an hour.
Diangana put in an industrious display for the away side but rarely threatened United’s goal
Karlan Grant – 5
Baggies’ best chance of the first half fell to him and forced De Gea into a good save.
Hal Robson-Kanu for Diangana 62 – 5
Callum Robinson for Grant 62 – 7
Filip Krovinovic for Ivanovic 79 – 5
Subs (not used) Button, Phillips, Harper, O’Shea.
Referee: D Coote 7