Craig Harrison said Hartlepool United were "killed" by Morecambe's first goal as they crashed out of the FA Cup 3-0 at the Globe Arena.
Pools were on the back foot from the outset, with Kevin Ellison firing the Shrimps into a fifth-minute lead.
The away side, roared on throughout by a travelling army of 854, came out strongly in the second period only to give away a poor second goal, Andrew Fleming scoring midway through the half.
Morecambe's 85th-minute match-clincher had a significant element of luck when a shot by former Pools loanee, Adam Campbell, came back off the post and hit Scott Loach and nestled in the away net.
“I think the first goal has killed us," he said. "It's given them an early advantage and we then have to take more risks.
"It takes the game management away from us.
“If we went in at 0-0 like at Torquay at half-time last week, then it's a different game.
"We've only lost once in the last 14 matches when we've gone in at half-time with no goals against and that Was Eastleigh when we had that mad five minutes.
"I felt if we could have ridden the first 10 to 15 minutes and grown into the game then the pressure would have turned on them.
"The home fans would not have been happy.
"It was very disappointing, I didn't think there was anything in the rest of the match, it was probably 50-50 after that, we had the more possession.
"But when you are one up you can let the other team have the ball
“We lost the game in the first seven minutes by not dealing with their intensity."
Harrison pointed to some astute game-management from the Shrimps as proving a difference.
After the re-start, Pools piled on the pressure only for a lengthy injury break to interrupt their flow.
"We've come out like a house on fire for the second half," said the manager. "But a player goes down injured and it takes the sting out of the game.
"It is what it is, game-management, it's just disappointing we are out of the cup.
"I'm no a one to go 'we'll concentrate on the league now, I'd have been happier concentrating on the FA Cup, FA Trophy and National League."