Marcus Rashford came off the bench to score a late winner and maintain Manchester United's winning start to the season, as they edged past Hull City 1-0 at the KCOM Stadium.
It looked like being the most frustrating of evenings for the Red Devils, who had 29 attempts before finally making the breakthrough in the second minute of added time.
Hull produced a fine defensive showing right until the last moments, but they could not hold on for the remaining few seconds to make it 11 defeats in their last 12 meetings against United.
Zlatan Ibrahimovic was involved in most of the visitors' best moments, much like he has been during the opening weeks of his United career, and came close to opening the scoring just nine minutes in.
A flat ball into the box was flicked goalwards by the former Paris Saint-Germain striker, skimming the roof of the net on its way through but not testing Eldin Jakupovic in the Hull goal.
City were certainly not willing to sit back, however, and they came close twice in quick succession a quarter of the way through when Robert Snodgrass sent a free kick narrowly wide, before marginally failing to get on the end of a fine Andrew Robertson cross.
Jakupovic had two saves to make soon after, keeping out a weak Paul Pogba attempt from 25 yards out and a Juan Mata free kick from slightly closer range as the Red Devils began to up the tempo.
Hull may have a poor overall record against their opponents, but that did not stop them from pushing on in search of an opener as Adama Diomande and Abel Hernandez both got attempts on target, which David de Gea barely had to break a stride to collect.
Mata also had a headed attempt kept out before the interval, generating enough power to ask questions of Jakupovic at the end of an Antonio Valencia cross, but United's best chance would fall the way of Wayne Rooney.
Jakupovic initially did well to keep an angled shot out, although unfortunately for him the rebound fell nicely to Rooney who was denied an opener only by the chest of Curtis Davies on the goal-line.
There was to be one more opening for Ibrahimovic late in the half, only for the free summer signing to send his back-heeled attempt into the side-netting after getting on the end of a free kick ahead of Jakupovic.
United took control of things for large parts of the second half but, Rooney's on-target header aside, they were struggling to create chances prior to the hour mark which forced Jose Mourinho into action.
On came Henrikh Mkhitaryan for the underwhelming Anthony Martial, soon to be joined by youngster - and matchwinner - Rashford for his first appearances of the campaign.
The final 20 minutes of the match well and truly burst into life, as Rooney - with 10 goals in his last six outings against the Tigers prior to today - sent a sweetly-struck volley narrowly wide to get the momentum going.
Hull were having to do plenty of defending, but they did occasionally get forward and could so easily have taken the lead when Tom Huddlestone's shot deflected heavily off Eric Bailly and dropped the wrong side of the post.
David Meyler then blocked a cross with his upper arm, with the referee Jonathan Moss quick to wave play on, before Rashford jinked his way through and looked to pick out the bottom corner - Jakupovic getting across to produce his first real save of the contest.
Mkhitaryan and Pogba both saw openings come and go in the final 10 minutes, the latter curling a shot off target with attempt number 28 of the evening for the visiting side.
Just when it looked as though United were about to drop their first points under Mourinho, up popped Rashford in added time with a close-range finish, marking a fine cameo appearance with what proved to be the winner.
