Michael Duff felt his team were second best throughout their Easter Monday visit to Lincoln City.
The Imps took all three points with a comfortable win having been three goals up within the first 20 minutes at the LNER Stadium.
Duff admitted his team were well off the pace as they slumped to defeat.
"I'd like to apologise to the supporters who have come a long way on a Bank Holiday weekend," he said.
"It's not been us very often so you've got to be careful because we've been lauded last week for breaking records.
"But it just reinforces the point that we are not a team that can just think we can turn up and enjoy the sun and pass it around, we've got to have more intensity in everything that we do.
"We didn't win any first contacts. They had players running past our players so it's a really disappointing afternoon."
Watch the press conference in full above on iFollow and on the EFL iFollow app.
There are just two games left this season and one final home match to come next against Bolton Wanderers on Saturday.
You can buy tickets for the visit of the former Premier League side online. Make sure you buy in advance to save £2 on matchday prices by buying before midnight on Friday.