The 18-year-old – making his first appearance of the season – steered home Wayne Rooney’s cross to spark wild celebrations on the away bench.Moments earlier, David Meyler had blazed over in a rare Hull attack.But it was a deserved win for United, who had gone close though Rooney, Zlatan Ibrahimovic and Paul Pogba.United and Chelsea are now the only Premier League sides with a 100% record from three games, with Manchester City – who have two wins from two games – playing West Ham on Sunday.Relive the late drama at the KCOM StadiumUnited find a wayRashford’s winner was the climax to a performance of persistence and intelligence from the visitors, who changed tack several times before eventually breaking down Hull.Ibrahimovic arrived at Old Trafford with a reputation for audacity, but, in the first half, it was his physical size rather than mercurial skill that posed most threat.Offering himself as a constant target in the box, the Swede headed just over the bar in the 10th minute before an extravagant backheel found the side-netting.The excellent Curtis Davies blocked the more direct route to goal after the break, but the guile of Henrikh Mkhitaryan and the pace of fellow substitute Rashford stretched the Hull defence in different directions and, finally, beyond breaking point.A back muscle injury which is likely to rule Marouane Fellaini out for several weeks means United will need to show similar adaptability when they meet Manchester City in their next matchTigers fall just shortWith Harry Maguire returning from injury on the bench, former Manchester United assistant manager Mike Phelan had a season-high 14 fit senior professionals available for Hull.But what his squad lacks in numbers, it makes up for in spirit.Alongside Davies, Sam Clucas impressed in midfield, while Adama Diomande and Abel Hernandez chased hard to make something from the few scraps in attack.Before Meyler’s late wasted chance, Tom Huddlestone saw a shot deflect just wide with David De Gea hopelessly wrong-footed as they briefly threatened a smash-and-grab victory.But, after wins over Leicester and Swansea in their opening two games, their 100% start to their top-flight campaign is over.The uncertainty over the club’s future might also be at an end, however, with vice-chairman Ehab Allam writing in the programme that the match could be his family’s last as owners, with takeover talks with a Chinese consortium well advanced.That deal may free up funds to supplement the Tigers’ threadbare squad – Tottenham’s Ryan Mason is a target – and help them continue to defy the Premier League’s usual rules of gravity.MOTD analysis on RashfordAlan Shearer: “I don’t think it will be long before he is a regular. It has to be absolutely brilliant for him at that football club, working, training and socialising with Zlatan Ibrahimovic and Wayne Rooney.”Ruud Gullit: “What I like about Rashford is that he goes straight past players. He gives you opportunities. I hope Manchester United manager Jose Mourinho considers him more because he’s a great player.”Man of the match – Curtis Davies (Hull)What they said:Hull manager Mike Phelan: “You are playing quality sides who bring quality off the bench, but I am proud of the players. They have put hard work in today without getting anything out of it.”The Hull players are good players, and good people. They are determined and earned the right to be at this level. They worked hard for 12 months to be here.”We have six points from nine and that is what dreams are made of with 13 players who are fit.”We have been trying extremely hard to get players in and now have a small window. We have two or three in the pipeline but they are not done.”Manchester United manager Jose Mourinho: “We deserved it and in a more comfortable way. We had an amazing mentality. We tried and tried and got it.”I tell the boys every day we have to go into every match to win. We know we will draw or lose matches but the mentality has to be go to win. Today they showed that.”Marcus Rashford gives new problems to the opposition so I am really happy with him and the team.”We want to be champions, we don’t want to start well, we want to finish well.”The stats you need to knowMarcus Rashford has scored in consecutive Premier League games for the first time. He now has six goals in 12 Premier League appearances.Rashford is the first teenager to score a Premier League goal for a team managed by Jose Mourinho.Manchester United have won their opening three games of a Premier League season for the first time since 2011-12.Hull have faced more shots than any other side in the Premier League this season (70), though have conceded just twice.Manchester United scored 90th-minute winner for the 18th time a Premier League games, and the first time since November 2015 v Watford.Ahmed Elmohamady has appeared in every one of Hull City’s 79 Premier League matches since the start of 2013-14.What’s next?After the international break Hull travel to Burnley on 10 September with Manchester United at home to local rivals Manchester City on the same day.