Markgraf needed a bit of prodding from her teammates to run from midfield into the penalty box to take the kick, but coolly smacked her shot into the lower left corner past Ireland goalkeeper Emma Byrne.
"I have 192 games with the national team and scored no goals," said Markgraf. "For the past 10 years, any time we've had a penalty opportunity that wasn't in a major tournament they've tried to get me to take one. Today I finally caved and said 'okay, I'll take one today.' Some of it had to do with being here in Chicago [where she will be playing in WPS for the Red Stars], but I also had to get rid of the pressure! Natasha Kai probably put the most pressure on me. She would always say 'I'm getting you a PK!'"
The first goal of the game came in the 19th minute when Carli Lloyd slipped a short pass into the penalty box for Lindsay Tarpley, who spun a one-touch right into the path of Lori Chalupny. The U.S. left back slipped the ball under Irish goalkeeper Emma Byrne from 10 yards out to give the Americans the lead.
Saturday's game marked the end of the first phase of the Achieve Your Gold Tour.
The U.S. women will hit the field again in November for the next matches on the Achieve Your Gold Tour. The dates and venues for the remaining seven games of the tour will be announced in the near future.
Sept. 20 in Bridgeview, Ill.
USA 2 Ireland 0. Goals: Chalupny 19, Markgraf pen. 31.
USA -- Solo (Barnhart, 46), Chalupny, Rampone (Buehler, 46), Markgraf, Mitts (Cox, 46), Hucles (Wagner, 46), Boxx, Lloyd, O'Reilly, Tarpley, Kai (White, 63).
Ireland -- Byrne, Tracy, Fahey, Moran (Boyle, 90), McCormack (Connor, 46), Grant, Hughes (De Burca, 46), McDonnell, O'Gorman;, O'Brien, Curtis (Thomas, 60).
Referee: Jennifer Bennett (USA).