A former math teacher from New Jersey will make history today at the World Cup as the first American to referee a knockout stage match.
Interested in ?Add as an interest to stay up to date on the latest news, video, and analysis from ABC News.
Mark Geiger, 39, who hails from Beachwood, was selected by FIFA to officiate the match round of 16 game between France and Nigeria in Brasilia.
Geiger refereed Chile's 2-0 victory over Spain and Colombia's 3-0 routing of Greece during the group stage.
He is the first American to work a World Cup match since Brian Hall in 2002, according to US Soccer. At previous World Cups, Americans have only officiated during the group stages of the tournament.
Geiger got his start on the international stage in 2011 when he was chosen as one of the referees for the U-20 FIFA World Cup in Colombia. He was also named the Major League Soccer Referee of the Year in 2011.
The transition from teacher to referee has been seamless for Geiger, who compared giving out yellow and red cards to detention and expulsion.
Knowing one misstep could ruin his chances of working a FIFA game, Geiger told the Los Angeles Times he focuses on each match as it comes.
"It could happen, I suppose," Geiger said of his chances of lasting to the championship game in Rio on July 13. "Coaches, players, they all dream of having the final. That's what we're working towards and we're going to work very hard in order to accomplish that."
"But if we don't perform well in that very first game, there's no possibility of us getting the final. So all of our energy and focus is going to be on that first game. And then we take it from there," he added.
While he'll be the most prominent American at the World Cup today, Team USA will take center stage Tuesday when they play Belgium for a place in the quarterfinals.
The Associated Press contributed to this report.
Sign up for occasional World Cup dispatches from Brazil delivered right to your phone -- including the best photos and limited highlights -- by "starring" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.