Ride entered the University of California, Los Angeles, where she enrolled in courses in Shakespeare and quantum mechanics, earning A's in both subjects. She was the only woman majoring in physics. She was romantically involved with the teaching assistant, John Tompkins, but the relationship ended in September when he went to Moscow to conduct research at the Institute for High Energy Physics. Her foray into professional tennis was unsuccessful; after playing three matches in a single August morning her whole body ached the following day. She realized that far more effort would be necessary in order to reach the required level of fitness: she needed to practice for eight hours a day. She concluded that she did not have what it took to be a professional tennis player.