‘Believe in yourselves more. You might have won that game if you’ve had more belief.’
There might be a frustration among the group that they merit more than the six points they have returned from the opening five games.
Unlike last season, Rovers are also quickly discovering that teams at this level are not quite as easy to brush aside or put to bed.
And the lacklustre display at AFC Wimbledon might just have knocked confidence slightly in the build-up to facing the division’s form team.
But there is no reason at all why anyone in the Doncaster camp should be lacking any self-belief or suffering any mental fragility right now.
For starters, they only need to take a look around at the quality within the current squad.
A prime example of that is loanee Jordan Houghton who made his return from injury as a second half substitute against the Posh and looked liked he had never been away or indeed injured.
After a mainly encouraging start to the season that has included eye-catching wins at Blackburn Rovers in the league and at Bradford City in the Carabao Cup, there should be no lack of collective belief.
Rovers are creating chances at one end and at the other they look well disciplined, with young centre back Joe Wright busy grabbing his opportunity with both hands.
On Saturday they became the first side to stop a Posh team averaging three goals per game scoring, and they more than held their own against a club expected to challenge at the top end of the table.
Like so many times last season, they also successfully managed to bounce back from a poor performance, nipping that bad defeat at Kingsmeadow in the bud.
So a third successive home draw, all in all, was slightly disappointing and frustrating, yes.
But, on the whole, there are plenty of signs that Rovers can flourish in this division and there is no real reason why anyone should be lacking in belief.
THE STORY OF THE MATCH
Was it belief that Doncaster lacked? Or were they just missing a clinical edge?
Rovers arguably had the best chance of the game during the early exchanges when a mistake from Jack Baldwin presented John Marquis with a clear sight of goal.
Marquis is yet to hit his straps, however, and fluffed his chance.
The game ebbed and flowed continuously. There might have been no goals but there was no shortage of entertainment or endeavour.
Rovers had to withstand a period of Posh pressure before the interval that saw Marcus Maddison, arguably the best player on the pitch, hit the bar with a curling effort and then go close with a deflected shot from distance.
Ian Lawlor had to be on his toes to block a stinging shot from Gwion Edwards and keep out an effort from Jack Marriott.
But it was the home side that came on strong after the interval, driving forward at every opportunity and enjoying the lion’s share of possession and territory.
They just lacked a killer ball or final product.
Alfie May might have done better once he got in behind Peterborough’s impressive three centre backs, Houghton saw a powerful shot blocked and only a last-ditch Baldwin intervention prevented substitute Andy Williams scoring from close range after good work from Ben Whiteman.
In the end a draw was probably a fair result.
HOW DO ROVERS TURN DRAWS INTO WINS?
There was a palpable sense of frustration and disappointment from Ferguson and his players after being forced to settle for a third successive draw on home soil.
The fact they have taken just three points from nine at the Keepmoat Stadium is disappointing when you consider the umpteen number of chances Rovers had in the games against Gillingham and Blackpool.
Having kept two clean sheets in three home games, Rovers will feel they ought to have taken a minimum of six points from the three home games.
They could have had nine.
But they are going to have to be more clinical in front of goal.
They are unlikely to keep on getting the number of chances in games that they had last season.
When the good chances come along, they need taking.
And when they get into good positions, the final ball needs to be much better.
There was a perfect example of that in the first half when Matty Blair beat his man, had all the time in the world to deliver, but his cross was cleared by the first man for a corner.
Perhaps Ferguson is right? Maybe this young squad do just need to stick their chests out and believe a bit more.
Like at Bradford and Blackburn, where they scored three on each occasion, they seem to very quickly grow in confidence when things click into place.
When things are tougher, like on Saturday, like at AFC Wimbledon, they just appear to require that little spark from somewhere.