Amber Marsh Elliott struck a shot with the 60-degree wedge, and immediately realized something was wrong.

“I knew as soon as I hit it that it wasn’t my club,” said Marsh Elliott, the 2003 U.S. Women’s Mid-Amateur champion from Greensboro, N.C., who was playing the seventh hole of Pacific Dunes with her partner, Katie Miller, in the U.S. Women’s Amateur Four-Ball Championship’s Round of 16 on Tuesday.

Miller, of Jeannette, Pa., was using a pull cart, while Marsh Elliott was employing a caddie, Richard Dillon. On the previous hole, Dillon had held a wedge for Miller while she putted, and he inadvertently put it into Marsh Elliott’s bag on the completion of the hole. The club was the same brand as Marsh Elliott’s, and when Marsh Elliott went to play a wedge shot on the next hole, she pulled Miller’s club. After the shot, she realized it was not her graphite-shafted club, but Miller’s steel-shafted one.

Marsh Elliott immediately informed Scott McNevin, the referee assigned to the match, and the side found itself in an unusual predicament. They had started the par-4 seventh hole with a 1-up lead, and walked onto the next tee trailing by one hole.

“It could have been a lot worse,” said Marsh Elliott, 46, who graduated from the University of North Carolina in 1992 and earned her amateur reinstatement in 1998. “It could have been a few holes later [when she discovered the extra club].”

Actually, simply carrying the extra club inadvertently was not an issue, since she had not started the round carrying it. As Rules official Bob Austin, of Greenwood Village, Colo., later explained, carrying a club that was accidentally placed in a partner’s bag would be a case of “no harm, no foul, no penalty.” As Austin put it, “There is no intent to break a Rule.” Only when Marsh Elliott hit a shot with the club was a penalty invoked: in this case, a one-hole adjustment to the state of the match.

Opponents Megan Carter and Lauren Lightfritz won No. 7 with a par to Marsh Elliott and Miller’s bogey, and the one-hole adjustment was assessed after the hole, per Rule 4-4b: “At the conclusion of the hole at which the breach is discovered, the state of the match is adjusted by deducting one hole for each hole at which a breach occurred.” The maximum deduction in a match is two holes, but in this case it was only one hole because it was caught right away.

Marsh Elliott and Miller gathered themselves and rallied to earn a 2-and-1 victory, clinching the match by winning No. 16 with a birdie and No. 17 with a par.

“We just said, let’s hit fairways and greens,” said Marsh Elliott of their mindset after the penalty, and their demeanor did not waver.

“It was a pretty big swing, but they battled through it,” said McNevin, who is the executive director of the Junior Golf Association of Arizona. “They stayed very calm and composed through the whole thing.”

Marsh Elliott, who underwent a bilateral mastectomy in 2006, just 17 months after her son, Justin, was born, was an assistant women’s golf coach for North Carolina who recruited Miller for the Tar Heels, but left before Miller came to Chapel Hill. Miller, a 2007 UNC grad, was planning to play in the Women’s Four-Ball with Marsh Elliott’s niece, Sydney Crane, but teamed with Marsh Elliott when Crane could not play.

Before the pair went out for their afternoon quarterfinal match, Marsh Elliott joked that Miller, 30, who has competed in seven half-marathons, would provide the stamina needed to get the 10th-seeded team through to Wednesday’s semifinals. They fell to the No. 2 seeds, Robynn Ree and Hannah O’Sullivan, 4 and 3.

Future Looks Rosy for USC

Andrea Gaston, the head women’s golf coach at the University of Southern California since 1996, is busy preparing her No. 1-ranked Trojans for the upcoming NCAA Championships after winning a sixth straight regional title earlier this month. But she is also likely keeping an eye on the results coming in from the 2015 U.S. Women’s Amateur Four-Ball.

Three players who reached Tuesday’s quarterfinal round have committed to enroll at USC. The team of Robynn Ree (class of 2015) and Hannah O’Sullivan (class of 2016) advanced to the semifinals with their third consecutive impressive win, defeating Miller and Marsh Elliott. Another player who has committed to USC, Muni He (class of 2017), advanced to the quarterfinals on Tuesday with teammate Angel Yin before losing to Mika Liu and Rinko Mitsunaga in 21 holes.

Statistical Notes from the Championship

In the Round of 32 on Monday, 15 of 16 matches were won by the higher-seeded team, with only the No. 22 seed, four-time U.S. Women’s Mid-Amateur champion Meghan Stasi and Dawn Woodard, advancing over No. 11 Patricia Wong and Katherine Muzi, 4 and 3.

In the Round of 16’s eight matches, the lower-seeded side won half of them, with Stasi and Woodard the lowest seed to advance, earning a 3-and-1 victory over No. 6-seeded Lila Barton and Marissa Barr, 3 and 1. The quarterfinals were likewise an even split, with Nos. 2 and 3 advancing, and No. 1 seeds Athena Yang and Kendall Griffin and No. 5 seeds Angel Yin and Muni He losing.

Madelein Herr and Brynn Walker won their first two matches in extra holes (20 holes in the Round of 32, 19 holes in the Round of 16) before eliminating Stasi and Woodard, 5 and 3, in the quarterfinals.

The average age of the field has progressed downward throughout the championship, with the exception of the quarterfinals (number of players in parentheses):

• All entries (336) – average age of 44
• Championship field (128) – average age of 33.7
• Round of 32 (64) – average age of 24.3
• Round of 16 (32) – average age of 19.7
• Quarterfinal round (16) – average age of 21.9
• Semifinal round (8) – average age of 16.9.

Ron Driscoll is the manager of editorial services for the USGA. Email him at rdriscoll@usga.org. Tom Mackin is an Arizona-based golf writer and a frequent contributor to USGA websites. Email him at temackinjr@gmail.com.