James Walker, Elliot Ward, and Mark Noble all started for the first time while Trent McClenahan made his home debut.
"I thought they did well, especially in the circumstances they were all thrown together," says Peter.
"If you had said at the start of the season that your back four would have included Trent McClenahan and big Wardie in your back four you would have said 'what?'
"But especially in the second half they did it when we we were under a lot of pressure.
"People don't realise there is a big difference from the reserves and there is an adrenalin thing you have to deal with.
"You have excitement, nerves, the crowd, and all of a sudden there is expectation - so there is a different kind of pressure.
"They did well, and they were tested on Tuesday because, to be fair, Southend put us under pressure in the second half.
"They withstood that, and, looking further up the pitch, it was good to see Mark Noble on the field, as well as Chris Cohen playing and Darren Blewitt on the bench.
"James Walker came in and used his experience to the full, so we went from one extreme to the other with the youngsters as well as an older player making his debut."
Peter agrees with Alan Pardew that James' time in the limelight is long overdue and adds:
"I have always known, for his 10 years at Walsall, that he was a fantastic keeper.
"People maybe questioned the fact that he lacked a couple of inches but his experience served us well on Tuesday and I was delighted with him.
"He has been first class the minute he walked into training, not just for the way he goes about his job but for the fact that he has a wee bit about him - a bit of banter.
"He helps Stephen Bywater a lot as well and the two work very closely together, alongside Ludo - it proves that all the hard work is well worth it."
Injuries played a major factor in Trent and Elliot starting against Southend, and Peter adds:
"Some people's careers kick off because of other people's misfortune and nine times out of 10 a player gets a debut because someone else is suspended.
"These boys got the opportunity and they did themselves justice - they did fine.
"Now they have to try and maintain that; the way it is at this club is that you will be given an opportunity at this club if you are good enough.
"Look at Trent; he probably hasn't even travelled with the first team before but now he has played two games in four days.
"That is the way football works."