The City defender reached the milestone as the World Champions defeated Mexico 4-0 in their Send-Off Series - their penultimate game before the Tokyo Olympics.
Dahlkemper, who has been selected to take part in the Games for the first time, kept her ninth successive international clean sheet and produced an excellent block to deny Maria Sanchez a leveller after Sam Mewis had opened the scoring.
The former City midfielder drilled into the near post, having been teed up by her sister Kristie for the first sister assist-goal combo in the country’s history.
Christen Press extended the lead before the break, converting Megan Rapinoe’s cut-back, and doubled her personal tally with five minutes remaining, after Tobin Heath had made it three.
Dahlkemper, making her 63rd start in her 70 appearances, completed the full 90 minutes to help the Stars and Stripes reach their second-longest unbeaten streak of 43 matches and 19th straight home win.
The USA will face Mexico again on 5 July (17:00 ET, 22:00 UK time) at Pratt & Whitney Stadium at Rentschler Field, Connecticut in their final game before the Olympics.
