Gary Bowyer felt that there was room for improvement after Saturday's 2-2 draw with Rochdale.
Rovers were slow out of the blocks at Spotland and paid the price when Scott Hogan fired the home side in front after just 12 minutes.
A Jordan Rhodes header and an Alan Judge free-kick that hit the post were all that Rovers had to show for in a poor first half that was compounded when Peter Vincenti doubled Dale's lead moments after the restart.
However the introduction of Josh King and DJ Campbell changed the game in favour of Rovers, Campbell netting sixty seconds after his hour mark introduction after good work from Judge.
Rovers continued to press but just when it looked like they would taste defeat in pre-season for the first time, Morten Gamst Pedersen stepped up to curl a wonderful 20 yard free-kick into the bottom corner to level the scores in injury time.
"In the first half we were poor," said the Rovers boss after the game. "I just had a chat with the players there and it didn't need me to tell them that they weren't very good.
"I think the only thing we had to show in the first half was a great free kick from Alan Judge and a good cross from Josh Morris for Jordan's header.
"Apart from that we looked off the pace, we looked tired a little bit and we were disappointed with how we had gone about the game.
"We made some substitutions, Matt Kilgallon came on and did ever so well out of position as he's a more natural centre half, and also I thought Josh King and DJ Campbell especially were very good and changed the game for us.
"You have to try and take the positives out of it and the positives are that we've now learnt that we cannot just turn up and expect to play. You have to earn the right and Rochdale denied us that right and we've got to be better than what we were when a team comes against us and shows a little bit more hunger.
"The positives out of it are that DJ Campbell was excellent and his goal was great and then a fabulous free kick from Morten at the end.
"So there are things to build on that is for sure, there is a lot of work to be done. People are getting their opportunities now to stake a case for the starting eleven.
"We are two weeks away and we need to sharply improve now.
"Pre-season has all be detailed and planned and the first 45 is our first blip. We now go into a local derby again on Tuesday night and we've got to show a higher level of performance than we did in the first half against Rochdale that is for sure."
Tickets for the game at Deepdale this Tuesday are currently on sale and will be available from the ground on the day of the game, priced at £10 for Adults/Seniors, £1 Under-16s.