Question: Who is older, Sergio Casal or Gabriela Sabatini?
Context: Gabriela Sabatini was the defending champion but did not compete that year. Steffi Graf was the two-time defending champion, but she was defeated in the final by her rival Gabriela Sabatini, in what was a rematch of the 1988 US Open final and the 1989 US Open top half semifinal.  It also proved to be the first and only time Sabatini would defeat Graf in Grand Slam competition. Gabriela Beatriz Sabatini (] ; born 16 May 1970) is an Argentine former professional tennis player.  She was one of the leading players on the women's circuit in the late-1980s and early-1990s.  She won one women's grand slam singles title at the US Open in 1990, the women's grand slam doubles title at Wimbledon in 1988, two WTA Tour Championships titles in 1988 and 1994, and a silver medal at the 1988 Olympic Games in Seoul. Steffi Graf successfully defended her tile, defeating Monica Seles 7–5, 6–4 in the final to win the Women's Singles title at the 1996 US Open.  It was a rematch of the 1995 US Open final, where Graf defeated Seles in three sets.  It also marked the final time Seles and Graf would play each other at the US Open.  The 1996 U.S Open proved to be the last for Gabriela Sabatini, as she retired later that year.  Sabatini was twice a finalist at the U.S Open.  In the 1988 US Open final, Sabatini lost to Graf in three sets.  Two years later, at the 1990 US Open, Sabatini defeated Graf in two sets to win her only Grand Slam title. Steffi Graf and Gabriela Sabatini are retired professional tennis players who played each other on 40 occasions between 1985 and 1995.  Steffi Graf was the world No. 1, whilst Sabatini reached a career high of No. 3.  They are both Grand Slam Champions, the German winning 22 titles whilst Sabatini won her only Grand Slam title against Graf.  The pair also teamed up to reach three French Open finals and won the 1988 Wimbledon crown. Steffi Graf was the defending champion going into the final against her rival Gabriela Sabatini.  Just the previous month, Sabatini defeated Steffi Graf 3–6, 6–3, 7–5 in the final at Amelia Island, Florida.  Now, in her native Germany, Steffi would turn the tables against Sabatini, beating her 6–3, 6–1.  Prior to this match, Sabatini had played in four finals in 1989, with her winning twice.  For Steffi, this victory was her seventh of the year, and marked the sixteenth time out of nineteen matches she had beaten Sabatini. Sergio Casal Martínez (born 8 September 1962) is a former professional tennis player from Spain.  During his career, he won three Grand Slam doubles titles, as well as the men's doubles Silver Medal at the 1988 Summer Olympics. Steffi Graf and Gabriela Sabatini were the defending champions but did not compete that year. The 1988 Virginia Slims of Florida was a women's tennis tournament played on outdoor hard courts at the Boca Raton Resort & Club in Boca Raton, Florida in the United States and was part of Tier II of the 1988 WTA Tour.  The tournament ran from March 7 through March 13, 1988.  Fourth-seeded Gabriela Sabatini won the singles title and earned $60,000 first-prize money, ending a 30-match winning streak by Steffi Graf.  It was Sabatini's first win over Graf after 11 previous defeats. Steffi Graf was the defending champion but lost in the semifinals to Gabriela Sabatini.
Answer: Sergio Casal