Manager Graham Coughlan admitted his Mansfield side were outplayed and outclassed after falling to a 4-0 Carabao Cup defeat at Championship side Preston.
Goals from Tom Barkhuizen, Sean Maguire, Patrick Bauer and Josh Harrop did the damage as North End proved far too strong for their League Two visitors at Deepdale.
And for Coughlan, the result and performance proved a rude awakening ahead of the league campaign.
"That was a harsh lesson for us to take," he said. "I thought they were excellent, they were the best team by far.
"They were pushing for a Premier League place at the end of last season and they'll be pushing for a Premier League place at the end of this season.
"There's 55 places between the two clubs and it did show, but overall I'm really disappointed with the goals we conceded. We could have done far better, we gave away the ball far too cheaply.
"When you give the ball away against a team like Preston then you're going to be in trouble.
"All-in-all we're young and we're developing. We're a long way off but we just need to be more clinical in front of goal. We can't make excuses though, they are a class outfit and were much better than us."
Barkhuizen rifled into the bottom corner while Maguire produced a splendid strike to put Preston two up after 22 minutes.
Bauer made it 3-0 on the half-hour and Harrop rifled home the fourth in the second half.
"I'm really pleased, especially because we've only been back two weeks," said North End boss Alex Neil. "To win any game by four goals is really pleasing.
"We picked a team that we felt would be really suited to the way Mansfield play. They're really aggressive, but we knew there was going to be space in behind and we were really quite dynamic at the top end of the pitch.
"I thought we started the game sloppy. We gave the ball away quite a few times on the left-hand side and their early chance came from us pressing the ball. They hit the post but it proved to be a bit of a catalyst where we kicked ourselves into gear.
"I thought we got the balance spot on, some of the quality up front was excellent. It's good for the players' confidence that we had a lot of our forward players getting goals.
"I think there's certainly things we need to work on. We need to make sure we hit the ground running and also make sure we don't take our foot off the gas when we're in charge of teams."