Benning achieved her highest placement at the World Cross Country Championships in 1984, finishing sixth in New Jersey. Then in the summer, she added the AAAs 1500 m title to her previous wins at 800 m and 3000 m. At the 1984 Los Angeles Olympics, she reached the 1500 m final, finishing fifth in 4:04.70. She ended the 1984 season by running her best ever times in both the 3000 metres and the mile, with 8:44.46 in Zurich and 4:24.57 in London.