The vote of confidence comes the day after Posh were knocked out of the FA Cup at home by Kidderminster, whose 3-2 victory on Tuesday night saw the Skrill Premier side become only the second non-league team to beat Posh at London Road in the competition in the past 54 years.
The defeat follows four successive league losses that have seen Peterborough fall off the pace in the race for automatic promotion from League One.
It got worse for Posh as Walsall's win over Oldham on the same night saw the Saddlers replace Ferguson's men in the play-off places.
But MacAnthony has used his Twitter account to back his beleaguered boss, and also hinted at the arrival of some new players during the January transfer window.
"I have stayed off Twitter for obvious reasons (in the) last few days as I feel at the moment talk is cheap and that's the last thing our fans need, especially with our recent run of results and last night's embarrassment when we let them down again," said MacAnthony.
"The flak is non-stop from all angles and deservedly so considering these results. So what I can do is do my best to support a management team who have worked with my club for many years and brought it all its success in the period I have owned it.
"The players don't need me or you to tell them how poor it's been. They set their own standards and have fallen way below them as we all know.
"What I/we can do now is focus and support the staff/players in working hard to rediscover their form/confidence to get the season back up and running.
"I will do my part and support them all by working hard in bringing some freshness to the squad and one hopes we see the hard work/perseverance pay off in the two home games we have coming up.
"Nobody ever said owning/supporting or playing for a football club is a walk in the park, (it's) full of highs/lows. So it's now up to all of us at the football club to give our fans the highs they want as quickly as possible and deal with the adversity as best we can whilst doing so.
"I thank the Posh fans who continue to come (and) support us no matter the result and have no doubt the players look forward to hearing you this Saturday!"