The US led 3-1 after the opening fourballs session, but were whitewashed 4-0 in the afternoon foursomes.
Four-time major winner McIlroy was the only player in the morning fourballs on either side not to register a birdie as he and rookie Thorbjorn Olesen were defeated.
But he bounced back alongside Ian Poulter in the foursomes with a 4&2 win over Bubba Watson and Webb Simpson.
Heroes of the day, however, were Open champion Francesco Molinari and Tommy Fleetwood, who beat the USA’s premier pairing of each session.
They dispatched Tiger Woods and Patrick Reed 3&1 before returning to smash Jordan Spieth and Justin Thomas 5&4.
Immediately after his round Bjorn gave Fleetwood just an hour off to celebrate what remained of son Franklin’s first birthday.
But it was Bjorn’s faith in McIlroy, which many questioned after watching him in the morning, that was repaid the most.
“I never have any doubt in Rory McIlroy because if I start doubting him then I probably shouldn’t be doing this job,” said the Dane, whose side turned around a 3-1 deficit to lead 5-3 with the Europe’s first foursomes whitewash in the history of the event.
“I believe in him and it was great to see his response. But that’s more on him.
“I was never in doubt that I wanted to have him on the golf course [in the afternoon]. I had a plan and I stuck to it for this first day, and I’ve had it for a few days.
“Great players when they don’t perform to the standards that they want to have an ability to just go and prove to themselves, they want to put it right, and he did that.
“The only thing I said to Rory is, ‘We go again’. It was a bad morning. He didn’t play well, and you go again. You go out there and you bring a different type of game.
“But I made it quite clear all along that I’m not in any way qualified to tell Rory McIlroy how to play golf.
“But I’m qualified to lead him in a direction with the people he’s surrounding himself with this week to get good things out of him and he is a guy that only needs very short comments and then he goes again.”
Fleetwood needed no advice from his captain having gelled brilliantly with Molinari, with whom he will play in today’s morning foursomes against Woods and Reed again.
It was a European partnership that worked brilliantly and one both players said they enjoyed.
“Tommy is on his way back to the hotel to spend an hour or so with his son, and that will be nice for him,” Bjorn said.
“That’s a pretty special thing for him and for Clare (Fleetwood’s wife). That’s been agreed a long way in advance that that was going to happen.
“I couldn’t promise Tommy that he was going to play two sessions [yesterday] so there was a few different ways of doing it. Now he’s on his way back to the hotel to have a little bit of time with his family.”
On the success of the Molinari-Fleetwood pairing, Bjorn added: “You’ve got a former French Open champion and the Open champion.
“They just love playing with each other. I think they just have a very special bond and relationship, and they have for a long time, and they love being on the golf course together.”
On Europe’s historic foursomes whitewash, Bjorn said: “It’s a pretty special occasion obviously, for those players that they have done that.
“But they are also very well aware that you can enjoy this for about an hour and then you turn around [to today] and you start focusing on what’s ahead of us.
“We know it’s a marathon, and we’re delighted with the way the day turned out, because it was a fairly tough morning. They wanted to go out and prove something, and that was nice to see, but it says a lot about the group.”
Report, more reaction, score details and second-day fourball pairings: Page 8.