The 1991 Ryder Cup player, who has stormed on to the over-50s circuit with four victories on the Staysure Tour and two further wins on the US PGA Tour Champions, carded the joint-lowest third round in the Championship’s history with a seven under par 64, moving to 11 under par at Harbor Shores Golf Club.
Starting his day with five birdies on his first six holes, and then adding another at the par four eighth hole, The 52 year old recovered from a bogey on the 12th hole with two further gains to finish seven under par on the day.
"Everything was going along nicely," said Broadhurst. "But you're not going to keep that sort of momentum going for 18 holes, then the run slowed down a bit in the middle. I had a poor bogey on 12, but bounced back with birdies on 14 and 15. I finished solid over the last three so I'm really pleased.
"The more you're in the last two or three matches the more comfortable you feel. Hopefully it will stand me in good stead.
"I guess I came out victorious at Carnoustie, but there are some top players up there. Scott's been playing really well recently and Miguel won last week, so I'm going to have to shoot four or five under again tomorrow."
He sits in third place behind joint-leaders Tim Petrovic and Scott McCarron, who won his first Senior Major Championship at the Constellation Senior Players in 2017. The American pair are 13 under par after 54 holes.
McCarron said he has learned from playing alongside Bernhard Langer, who secured a record tenth Senior Major Championship at last year’s Senior Open.
“I've been fortunate enough to play with him in a lot of final groups and second to last groups and battled it out with him and watch him," said McCarron, who was runner-up to Broadhurst at Carnoustie in 2016.
“The way he conducts himself around the golf course, doesn't let too many things bother him. So I learned a lot from him, just being really patient, so I don't really let that kind of big moment really get to me too much, just kind of control your emotions going through the day, and that's the biggest key for me.”
Miguel Angel Jiménez, who won his maiden Senior Major at last week’s Regions Tradition, birdied four of his first five holes in Michigan, making the turn four under par. He made two further gains on the back nine to move to nine under par.
Colin Montgomerie, a two-time winner of the Senior PGA Championship, is joined by fellow staysure Tour members Jesper Parnevik and Chris Williams in ninth place on seven under par, and 2002 Ryder Cup player Phillip Price carded a four under par round of 67 to move to 18th place alongside 1993 Ryder Cup player Barry Lane on six under par.