"The Pope rested well, the whole night," the Vatican said on Tuesday in a typically brief morning update.
On Monday evening, doctors said he remained in critical condition with double pneumonia but reported a "slight improvement" in some laboratory results.
In the most upbeat bulletin in days, they said he had resumed work from his hospital room, calling a parish in Gaza City that he has kept in touch with since the war there began.
After night fell, thousands of faithful gathered in a rain-soaked St Peter's Square for the first of a nightly recitation of the rosary.
The prayer evoked the 2005 vigils when St John Paul II was dying in the Apostolic Palace, but those on hand said they were praying for Francis' recovery.
Standing on the same stage where Francis usually presides, the Vatican secretary of state, Cardinal Pietro Parolin, said that ever since Francis had been hospitalised, a chorus of prayers for his recovery had swelled up from around the world.
"Starting this evening, we want to unite ourselves publicly to this prayer here, in his house," Parolin said, praying that Francis "in this moment of illness and trial" would recover quickly.
The Argentine pontiff, who had part of one lung removed as a young man, has been hospitalised since February 14 and doctors have said his condition is touch-and-go, given his age, fragility and pre-existing lung disease.
But in Monday's update, they said he had not had any more respiratory crises since Saturday, and the flow and concentration of supplemental oxygen has been slightly reduced.
The slight kidney insufficiency detected on Sunday was not causing alarm at the moment, doctors said, while saying his prognosis remained guarded.
Francis' right-wing critics have been spreading dire rumours about his condition, but his allies have cheered him on and expressed hope that he will pull through.
Many noted that from the night of his election, Francis had asked for the prayers of ordinary faithful, a request he repeats daily.
"I'm a witness of everything he did for the church, with a great love of Jesus," Honduran Cardinal Oscar Rodriguez Maradiaga told La Repubblica.
"Humanly speaking, I don't think it's time for him to go to Paradise."
Maradiaga, a founding member of Francis' inner circle of cardinal advisers, said he himself had been near death with COVID-19, on high flows of oxygen like Francis.
"I know the Pope may be suffering and as a result I feel closer to him in prayer."
