Rasmus Hojlund scored twice as Manchester United won a chaotic Europa League encounter against Bodo/Glimt 3-2 on Thursday, giving Ruben Amorim a vital win in his first home game at Old Trafford.
Alejandro Garnacho gave the home side a lightning start after a shocking error from opposition goalkeeper Nikita Haikin.
But Hakon Evjen levelled for the Norwegians and Philip Zinckernagel surged down the right wing to give them a shock lead.
Hojlund pulled United level with a superb finish just before half-time and poked them ahead early in the second period.
New United boss Amorim said the match was a "real ride" and that he was on a steep learning curve as he gets to know his players.
"Of course I see what everybody sees -- good moments, difficult moments, some confusion in the end trying to hold the result, but the lads did a great job," Amorim told TNT Sports.
"They ran, they pressed, they tried to do the thing we worked for these three days and we won."
And he said he was touched by the reception he was given by the home fans.
"The first thing is that half of the stadium doesn't know me, doesn't really know me," he added. "I came from Portugal. I did nothing for this love yet so the way they made me feel at home, it's so special."
The former Sporting Lisbon boss, who has said his methods will take time to implement, made six changes from the side that laboured to a 1-1 draw against Ipswich in his first game in charge on Sunday.
Tyrell Malacia returned to the United line-up for the first time since the final game of the 2022/23 season.
Bodo/Glimt also made multiple changes with one eye on domestic matters -- they are top of the Norwegian league table by a point with one match to come.
- Old Trafford welcome -
Amorim waved to the fans and was besieged by photographers as he took his seat at an expectant Old Trafford for the first time.
And within seconds he was celebrating a goal as United scored even earlier than they had at Ipswich -- within the first minute.
There appeared to be little danger as the ball was played back by Jostein Gundersen to Haikin but the goalkeeper let the ball run and Hojlund was on him in a flash.
Haikin scrambled to rescue the situation but the ball fell to Garnacho, who poked home.
The home side were on the front foot, with Mason Mount and Bruno Fernandes both forcing saves.
But Bodo/Glimt were playing some neat football and equalised following a fine move when Sondre Brunstad Fet found Evjen, whose rising finish gave Andre Onana no chance in the 19th minute.
Just four minutes later the bouncing hordes of yellow-shirted away fans were celebrating again, with United's fragile defence again exposed.
Patrick Berg freed Zinckernagel and the forward surged onto the ball, outmuscling and outpacing Malacia before finishing through Onana's legs.
United huffed and puffed as they tried to get back into the game and levelled when Noussair Mazraoui crossed for Hojlund, who killed the ball with his left foot and drove home with his right.
The Portuguese manager replaced the rusty Malacia at half-time with Diogo Dalot, switching from his favourite back three to a back four.
Mount hit the top of the crossbar after good work on the left by Garnacho.
But United were back in the lead in the 50th minute when Mount's clever flick found Manuel Ugarte, who crossed for Hojlund to tap in.
The home side wasted a number of chances and Onana was called into action in stoppage time to push out a Berg free-kick as United just about got over the line.
United sit 12th in the standings, with two wins and three draws from their first five games in the new-format league phase.