Kelly Maxwell, Travis Long and Gus Ulrich are tied for third place at 3-under-par 69. Mark Fuller, Darrell Kestner, Rich Steinmetz and Rob Moss are knotted in sixth place at minus-2.
Mielke, the head pro at Mill River Club in Oyster Bay, New York, began on the back nine and promptly bogeyed his first hole. He collected a pair of birdies in his last three holes on the front side, then birdied his first two holes on the second nine.
Mielke, who teamed with Rick Hartmann to finish as the runner-up in the inaugural Big Stakes Match Play Championship, bogeyed four, but ran off back- to-back birdies at six and seven to get into a share of the lead.
Morin, the assistant professional at The Falls Country Club in Lake Worth, Flordia, also started on 10, and like his fellow co-leader, bogeyed the 10th. He birdied 14 and 16, then added birdies at four, five and seven to shoot his 68.
Jeff Martin, Jim Sobb, Tom Tobey, Mark Yannotta, J.C. Anderson and Tom Herzan are tied for 10th at 1-under-par 71.
Bob Sowards, the defending champion, struggled to an opening-round, 5-over 77 and is tied for 94th place.