Europe swept to an historic 4-0 lead in the morning foursomes, before claiming another win and three ties in the afternoon fourballs to hold a 6½ - 1½ advantage overnight.
"We’ve got some congestion and some signs [of illness],” Johnson said. “Things like that are unfortunate, sometimes the energy is a little low. But the ability and desire to go out and play is still there. Every one of them wants to play every match.”
Asked whether the illness had spread through the camp, he replied: “It kind of has, if I’m being honest. It’s spread through my team.”
“I mean, I think me and Scottie birdied, what did we say, 14, we birdied 14, 15, 16, 17, 18, and then lost by two,” Koepka said after the tied match. “So yeah. I mean, I want to hit a board and pout just like Jon Rahm did. But, you know, it is what it is. Act like a child. But we’re adults. We move on.”
Europe captain Luke Donald sidestepped the opportunity to respond to Koepka’s comments, and insisted his side would not rest on their laurels after claiming a record-equalling five-point lead.
After enjoying an unprecedented clean sweep of the opening session, the home side also staged three dramatic comebacks in the afternoon fourballs.
“Unbelievable start, historic day, but we want it to be an historic week so the job is certainly not done,” Donald said. “We will all celebrate an amazing day, but we’ll be back with the goal of trying to win tomorrow morning’s session. We’ll be getting our guys focused to be back in the saddle, so to speak.
“We’ll enjoy the last hour [of play] and the celebration, but once I’m back at the hotel we’ll have a team meeting and we’ll be back to business.”
Donald was well aware that the United States could easily have ended the day just 5-3 behind as they were ahead in three of the fourballs on the closing stretch, only for Jon Rahm to finish eagle, par, eagle and Viktor Hovland to hole from 20 feet for birdie on the 18th.
Justin Rose then also birdied the last to ensure the five-point advantage and match Europe’s lead at Oakland Hills in 2004, when US captain Hal Sutton disastrously paired Tiger Woods and Phil Mickelson twice on the opening day.
Additional reporting by PA