The 23-year-old Mundorf's round of 63 at the Druid Hills Golf Club tied the U.S. Amateur record for stroke play, set Monday by Robert Godfrey of Clemson, South Carolina. The previous record for lowest 18-hole score in qualifying was 64, set by Phil Mickelson in 1990 and matched by Hank Kim in 1994.
Mundorf played the back nine first on Tuesday and was four-under after just seven holes.
'After that, I thought I'd be pretty safe to make the cut for match play,' said Mundorf. 'But I told myself, 'Don't start cruising or anything. Keep firing at it.''
Mundorf didn't let up and played the back nine in five-under par. He made three more birdies and eagled the par-five ninth hole to close out his 63.
Godfrey had a 63 at the par-70 East Lake Golf Club on Monday and managed an even-par 72 on Tuesday at Druid Hulls to finish tied for second in the stroke- play portion of the event at seven-under 135.
Michael Sims of Bermuda also finished tied for second in stroke play at seven- under after posting a six-under 66 on Tuesday at Druid Hills.
James Driscoll, last year's U.S. Amateur runner-up, tied for fourth at six- under after carding an even-par 72 Tuesday at Druid Hills. He opened with a six-under 64 at East Lake on Monday.
Defending champion Jeff Quinney, who sank a 30-foot birdie putt on the 39th hole to defeat Driscoll in the final last year at Baltusrol in New Jersey, earned a spot in the match-play field of 64. He finished tied for 35th in stroke play at even-par, playing both East Lake and Druid Hills in even-par.
Each player in the 312-man field played one round of stroke play at East Lake and Druid Hills. The remaining five days of play will be contested at East Lake.
The top 64 players in two rounds of stroke play gained spots in the match-play field.
The cut came at two-over 144 and 15 players were tied for the final two spots in the match-play field. Seven of the 15 players were eliminated on the first playoff hole.
Darkness then set in and the eight remaining players will vie for the final two spots when the playoff continues on Wednesday morning at 7:30 a.m. (et). The first round of match play will then begin.
Former champion John Harris was among those to miss the cut. The 1993 winner fired a three-under 69 Tuesday at Druid Hills, but it was not enough to overcome his seven-over 77 on Monday at East Lake.
Trip Kuehne, who lost in the 1994 final to Tiger Woods, also missed the cut with a two-day total of four-over 146.
Ty Tryon, the 17-year-old Florida high school junior who has indicated that he might turn pro after the Amateur, also missed the cut. He carded a four-under 68 on Tuesday at Druid Hills after stumbling to a 10-over 80 on Monday at East Lake.
Tryon became the youngest golfer in 44 years to make the cut in a PGA Tour event after he Monday qualified for the Honda Classic in March. Only 16 at the time, he finished the event in a tie for 39th.
He also played in last month's B.C. Open on a sponsor's exemption, shooting a 65 in the first round to tie for the lead. He posted 72-72-70 over the next three days and wound up tied for 37th.
Round Two Scores
Chris Mundorf,Raleigh, N.C.,71e-63d--134
Robert Godfrey,Clemson, S.C.,63e-72d--135
James Driscoll,Brookline, Mass.,64e-72d--136
Nick Watney,Fresno, Calif.,69e-67d--136
John Engler,Augusta, Ga.,70e-66d--136
Jerry Courville,Milford, Conn.,68e-69d--137
D.J. Trahan,Inman, S.C.,69e-68d--137
Lucas Glover,Greenville, S.C.,64d-74e--138
Ben Portie,Westminster, Colo.,66d-72e--138
Brock Mackenzie,Yakima, Wash.,69e-69d--138
Mike McCoy,West Des Moines, Iowa,73e-65d--138
Paul Simson,Raleigh, N.C.,69d-70e--139
Steve Sokol,Oxford, Conn.,71e-69d--140
Mike Plate,Ogallala, Nebr.,72e-68d--140
Wayne Raath,South Africa,,72d-68e--140
John Robertson,Olympia, Wash.,72e-69d--141
Bubba Dickerson,Hilliard, Fla.,69e-72d--141
Chez Reavie,Mesa, Ariz.,67d-74e--141
Matt Hendrix,Aiken, S.C.,72d-69e--141
Michael Carlisle,Aiken, S.C.,74e-67d--141
Jay Morgan,Choctaw, Okla.,71d-70e--141
Nicholas Thompson,Coral Springs, Fla.,69d-72e--141
Chris Wisler,Dover, Del.,66d-75e--141
Graeme McDowell,Northern Ireland,,66d-75e--141
Brian Quackenbush,Fairfax, Va.,71e-70d--141
Robert Hamilton,Carmichael, Calif.,67e-74d--141
Andrew Svoboda,Stamford, Conn.,73e-68d--141
Brian Nosler,Lake Oswego, Ore.,72e-69d--141
Casey Yates,Fouke, Ark.,70e-72d--142
Scott Hailes,West Bountiful, Utah,73e-69d--142
Andy Doeden,Fargo, N.Dak.,71e-71d--142
Kris Mikkelsen,Woodstock, Ga.,75e-67d--142
Daniel Summerhays,Farmington, Utah,68d-74e--142
Billy Harvey,Las Vegas, Nev.,75e-67d--142
Jeff Quinney,Eugene, Ore.,72d-70e--142
Steve Paramore,Ashland, Ohio,74e-68d--142
Sandy Horacek,Los Angeles, Calif.,74e-68d--142
Ryan Blaum,Coral Gables, Fla.,71d-71e--142
Michael Webb,Elberton, Ga.,71e-71d--142
Daniel Ozley,Birmingham, Ala.,74e-69d--143
Scott Abbott,Dallas, Texas,70e-73d--143
Brad Morris,Clay City, Ky.,68e-75d--143
John Carlson,Bagley, Minn.,75e-68d--143
Nick Cassini,Athens, Ga.,73d-70e--143
Chris Nallen,Hackettstown, N.J.,73e-70d--143
Scott Wingfield,Las Vegas, Nev.,69d-74e--143
Craig Steinberg,Los Angeles, Calif.,69e-74d--143
Brooks Kelly,Sierra Vista, Ariz.,69e-74d--143
Alan Morgan,Lake Charles, La.,72e-71d--143
Cameron Yancey,Blackstone, Va.,71d-72e--143
Jay Childs,Kennesaw, Ga.,74e-69d--143
Steve Christophel,Vacaville, Calif.,74e-69d--143
* Scott Feaster,Columbia, S.C.,69d-75e--144
* Greg Earnhardt,Greensboro, N.C.,73e-71d--144
* Advanced in Wedneday Morning Playoff
Notables Who Failed to Qualify
** John Davis,Mesa, Ariz.,73d-71e--144
** Thomas Lee,Guttenberg, N.J.,72e-72d--144
** Mike Booker,The Woodlands, Texas,70d-74e--144
** Matt McQuillan,Canada,,72d-72e--144
** Jeff Jenkins,Van Buren, Ark.,70d-74e--144
** Jonathan Dismuke,Calhoun City, Miss.,72e-72d--144
Chan Wongluekiet,Bradenton, Fla.,70d-74e--144(4)
Kevin Na,Diamond Bar, Calif.,71d-74e--145
Trip Kuehne,Dallas, Texas,74e-72d--146
John Harris,Edina, Minn.,77e-69d--146
Ty Tryon,Orlando, Fla.,80e-68d--148
Erik Compton,Miami, Fla.,75d-74e--149
David Eger,Ponte Vedra Beach, Fla.,77e-76d--153
** Failed to advance in Wednesday morning playoff