Barnes, whose appointment in June was his first in any coaching capacity, has been under pressure for several weeks after losing five matches out of seven, but this week's sale of Craig Burley plunged Celtic into apparent turmoil.
The transfer provoked criticism from several players led by Alan Stubbs, the captain, prompting talk of the club being "in revolt". At least half- a-dozen players were claimed to be considering leaving.
MacDonald, who was also appointed in the summer, appealed for time. "I know there is enormous frustration in terms of supporters wishing for success," he said, "but I don't believe anyone could have come in and been capable of producing a miracle.
"They won't be happy with what we're saying but good-minded people will give this team the time to get it right. We've had the worst decade in Celtic's history, we've also had seven managers. That says to me you need to bed down a management team and give them all the support and time they need to get things right."
MacDonald promised "substantial investment" but insisted it would be done in a "prudent manner", adding: "Celtic has faced the prospect of receivership and it is something we must ensure never happens again."
Dalglish was less effusive but was stirred on the subject of Barnes' future. "When I came in on July 1 I said I thought he could work at the highest level and I have seen nothing to change that. I have been watching him since pre-season and he has been tested in many ways, shapes and forms.
"We discuss things all the time, the matches, training, players, but I've not had any cause to go to John with any particular problem. If we don't produce the goods none of us are entitled to be here, we know that, but the last game [which Celtic won with 10 men] showed how much this club means to the players."Reuse content