The next two games will define Southend United's season according to boss Phil Brown.
Blues have lost their last two games in League One to Doncaster and Wigan Athletic.
But Brown says Blues must turn Roots Hall, where they are unbeaten in the league, into a fortress at an important stage in the season.
“Looking at the bigger picture these two important games, none more so than the first one of course, will define our season.
“What I want from these games is the pressure on myself and the players to actually keep a hold of the opportunity of hanging onto the shirt tales of the leaders, and I don’t mean the leaders as in Wigan, I mean the leaders as in the top six.
“You’ve got to be looking at winning your games at home, you’ve got to be looking to make saw that Roots Hall is a fortress, which we’ve made it.
“We haven’t been beaten at Roots Hall yet, and we’ve got to go in to the game with the positive performance from the weekend, not the negativity of the result.
“We hung on to their shirt tails and managed to get foothold in the game, even when we went down to ten men.
“We gifted them the second goal and that killed the game in effect and if we came away from the game 1-0 having after having a good go, then people would remember the performance, but because of that all people focus on is the 3-0 defeat.
“I think there were enough positives from Saturday, but the quality in the final third certainly has to improve if we want to do any damage to Peterborough’s back four.
“There a team that’s fragile at the moment, I think the last time they won was against Wigan, and they’ve lost four games since then.
“People are going to say is it a good time to catch them, and I’d say no, it’s not the case of the good time to catch them, you’ve got a wounded animal and a quality side and their in a similar kind of moment as what we are. We won four games on the bounce and now we’ve lost the last two quite heavily.
"They’ve not been picking up the results, and that damages confidence and damages belief systems and we’ve got to exploit that, we’ve got to take what we’ve got from Saturday and use it to a positive effect.
"Not only that but the home crowd behind us and Roots Hall in itself, being a fortress and being somewhere where we can win games of football.
“Unfortunately, Jermaine’s red card seems indefinable, which means he receives a three-match ban, so that’s one change we have to make ahead of tomorrow.
“There’s no new fresh injuries from the weekend which is great news, and one or two of the long-term injuries are on the training ground today, so whether I’ll take the chance and throw them in is something I’ve got to decide today."