Career
DeFina was included in the year-end top ten rankings issued by the United States Lawn Tennis Association from 1966 through 1968, reaching a career high ranking of seventh in 1967. Her best singles result at a Grand Slam tournament was reaching the fourth round of the 1967 Wimbledon Championships in which she lost to Ann Jones. In 1966, she reached the final of the United States. Women"s Clay Court Championships before falling to Nancy Richey Gunter.
In 1969, she was a doubles runner-up at the New England Women"s Invitational Indoor Tennis Championships (teaming with Kathy Pigeon) and was the singles runner-up at the United States. Indoor Championships.
She played the doubles match partnering Kathy Harter but lost to the sister team of Christine Truman Janes and Nell Truman.