Ole Gunnar Solskjaer admitted Manchester United were lucky to escape with a 3-2 win at Brighton thanks to a penalty from Bruno Fernandes, awarded on a VAR review after the final whistle had blown.
Brighton hit the woodwork five times and thought they had earned a deserved point when Solly March headed home to equalise five minutes into stoppage time.
However, Neal Maupay's handball was penalised by referee Chris Kavanagh after he consulted a pitchside monitor, having already blown for full-time, and Fernandes converted from the spot in the 100th minute.
Pre-season hopes that United could mount a title challenge to their biggest rivals Liverpool and Manchester City dissipated after a dire display in losing 3-1 to Crystal Palace last weekend.
And Solskjaer's were not much better on the south coast with Brighton boss Graham Potter lamenting "life is not fair" as United scored with their only shots on target.
"We got away with one. Maybe one point we deserved, we didn't deserve more," said Solskjaer.
"We've got to be honest enough to say they created the most chances. They had loads of shots, they had big chances and that's not what we want. We need to improve a lot in the few weeks coming forward."
Solskjaer again pointed to a shortened pre-season for his side's slow start as United had just a month between the end to last season and starting the new campaign.
"The spirit and character of the boys I don't question. The shaprness, fitness and the form will come," added Solskjaer. "We have a few weeks to catch up and the more games we play, we'll get better and better and sharper and sharper."
Leandro Trossard hit both posts with shots from outside the box, while Adam Webster's looping header came back off the crossbar as Brighton made the brighter start.
- VAR to the rescue -
The hosts finally got their reward when the tireless Tariq Lamptey burst into the box from right wing-back and was clipped by Fernandes.
The United midfielder was lucky to escape a second yellow card, but Maupay ensured they did pay the penalty with a cheeky chip down the middle of the goal as David de Gea dived to his left.
However, the lead lasted just three minutes as from a fiercely driven Fernandes free-kick, Nemanja Matic turned the ball back across goal and Lewis Dunk turned the ball into his own net.
VAR came to the rescue of both sides within the first 10 minutes of the second half.
Brighton thought they had a second penalty when Paul Pogba was penalised for pulling back Aaron Connolly. However, Kavanagh overturned his initial decision when he saw a replay of the incident.
At the other end, United's front three was beginning to click as Marcush Rashford swept home Mason Greenwood's low cross but this time VAR ruled against United with the goalscorer marginally offside.
There was no stopping Rashford moments later when he raced onto Fernandes's ball over the top and left Ben White trailing on the ground before his deflected effort found the top corner.
Brighton's bad luck continued when March became the next player to hit the woodwork as his low shot across De Gea came back off the inside of the far post before Trossard smashed against the bar with just the Spanish number one to beat.
The Seagulls seemed to finally have their reward when March ghosted in at the back post to head home Alireza Jahanbakash's cross.
But in a chaotic finale, Harry Maguire's header from a corner struck Maupay's arm and to Brighton's dismay, a penalty was awarded after Kavanagh had seemingly blown for full-time.
"Sometimes life isn't fair and it feels like that at the moment," said Potter. "The performance level was amazing from us, I'm so proud of the players. It's a sore one.
"I don't know what the shot count was but we were dominant. We deserved something from the game to say the least."
Fernandes has never missed a top-flight penalty and stayed cool under the pressure to ensure Solskjaer's men escaped with all three points.