Jim Bentley apologised to the Morecambe fans after what he described as an “unacceptable” performance from his side against Southend on Saturday.
The Shrimps crashed out of the FA Cup with a 3-0 defeat in the first round at the Globe Arena on Saturday.
Bentley said: “It’s very, very disappointing.
“The only two positives that have come out of today are Chris McCready and Marcus Marshall getting minutes on the pitch.
“But apart from that right throughout the team it wasn’t good enough.
“I’m not the type of person to accept what I’ve seen and I’ve told the players that.
“It’s the FA Cup, it’s the best competition in the world, we’ve got a home draw, it could be easier, but we didn’t show enough today.
“I’d like to apologise to the fans because that is not acceptable.
“If I could change three-quarters of the team next week I would do.
“I’m really hurting tonight.”
Morecambe never recovered from a disastrous opening 10 minutes in which Anthony Straker gave the visitors a 2-0 lead, with Ryan Leonard adding a third in stoppage time.
Bentley said: “We prepared them right and I said all I needed to say yesterday.
“I won’t use it as an excuse but we looked a little lacklustre in the warm-up after some of them arrived late because of the fire on the M6.
“It’s not us, I want us all firing in the warm-up but we took it into the game.
“It was a shocking first 10 minutes and that’s where we’ve lost the game.
“They worked harder than us, they chased us down, forced mistakes. I just can’t get my head round it - FA Cup football against a team that haven’t beaten us since we came up.
“I’m driving to the ground thinking: ‘I wish I was playing again’.
“It only comes round once a season. It’s not acceptable.”