Raymond Floyd, Jr., the son of 22-time PGA Tour winner Raymond Floyd, posted his second straight 2-under 70. He ended alone in second place at 4-under-par 140.
Danny Green, the 1999 Mid-Amatuer champion, shot an even-par 72 to take third place at minus-3. Green is one of six USGA champions that advanced to match play. Parker Smith, Kevin Marsh and David Noll, Jr. were one stroke further back at 2-under-par 142.
The Honors Course and the Black Creek Club were both used for the stroke-play portion of the event with The Honors Course slated to play host to the match-play portion of the championship.
Newhouse posted his 71 on the more difficult Honors Course. He spread four birdies and three bogeys over his 18 holes Sunday.
'I was definitely a little more relaxed because the pressure was somewhat off, unless I started off making a bunch of bogeys,' said Newhouse. 'But I started off okay and hit some good shots. This is a really tough, tight golf course and I think just having some additional room out there to miss some shots makes it easier to actually hit the shots.'
First-round leader Brendan Hester took seventh place at 1-under-par 143 despite a 5-over 77 Sunday. Tim Hogarth and Trip Kuehne were one shot further back at even-par 144.
Defending champion Austin Eaton III carded his second straight 1-over 73 to easily advance to the match play at 2-over-par 146.
Eleven players -- Fred McCord, Randy Nichols, Charlie Stevens, Greg Reynolds, Bryan Hoops, Sean Thayer, Dale Fuller, Steven Irwin, Robert Parker, Tom Scarrozzo and Brian Haskell -- will playoff Monday morning for the final three spots in the match play.
The match play portion begins with the first round on Monday. The second and third rounds will be played Tuesday, with the quarterfinal and semifinal matches on Wednesday. The championship will be completed with Thursday's 36- hole final match.