A brilliant chip-in eagle at the 18th means that DeChambeau spearheads the LIV Golf challenge heading into Sunday.
However, there is also a now significant European challenge at a tournament that has seen the Wanamaker Trophy hoisted aloft by a home player in each of the previous eight editions.
Left-handed MacIntyre continues to impress as he looks to become Scotland’s first major winner since Paul Lawrie, 25 years ago.
The 27-year-old has admitted to struggling to adjust to life in the US after joining the PGA Tour at the start of this year but had three weeks back in Oban before the championship and has him mum out for support in Kentucky.
“I’m going to get nervous but all I can do is try my best and see where we end up,” said MacIntyre.
“Until about probably the 68th hole I’m going to try and just play golf, and then at the 68th hole I have to maybe think about what I’m doing.”
Three birdies in the final four holes also turbo-charged Hovland’s round as he attempts to go one better than 12 months ago when he ended up as one of two runners-up to Koepka.
Belgian Thomas Detry also finds himself in a tie for 10th after a topsy-turvy 70 which included an eagle on the fourth.
While pre-round expectations largely centred on whether McIlroy could put a run together at a course where he won his fourth and last major in 2014, the man who partnered him to victory at the Zurich Classic of New Orleans earlier this month, was at the heart of most compelling storyline on Saturday.
Lowry was joint 29th entering the third round, eight shots off the lead. He shared 10 birdies with Rose across the first seven holes as the pair laughed and joked their way around Valhalla
“It was pretty cool out there, the two of us. It was nice to kind of bounce off each other and feed off each other the whole day,” said Lowry.
Rose, the 2013 US Open champion, added: “There was a nice energy about the group.
“You feed off the crowd, too. They could see me going well. They could see Shane going well. There were a lot of things pushing us all forward in the right direction, and once you got a sniff of the leaderboard, the intensity kind of goes up, as well.
“It keeps you focused and keeps you hungry and keeps pushing you forward.”