The three-time national champion eclipsed the 4,753 points by Hyleas Fountain and DeDee Nathan and her own personal best by 238 points on the first day of the three-day US indoor trials in Albuquerque, New Mexico.
"It makes me feel really good for two weeks for now," said Day-Monroe, one of eight heptathletes recently selected for the March 7-9 world championships in Sopot, Poland.
She set a lifetime best of 8.44 seconds in the 60m hurdles, cleared 1.88m in the high jump before setting a personal best in the shot put (15.59m) and an indoor best in the long jump (6.09m).
She concluded her day with a run of 2:13.19 in the 800m.
"Everything was just flowing and going really well, and I ended up with an American record," said Day-Monroe who had planned to only use the meeting as a warm-up for the world championships.
The US trials end on Sunday with world indoor pole vault record holder Jenn Suhr, Olympians Galen Rupp and Bernard Lagat and teenager Mary Cain among those seeking to make the American team.
- Sports & Recreation
- Hyleas Fountain