Who were the first brother and sister team to win a Grand Slam title together?

John Austin (born July 31, 1957) is an American former professional tennis player born in Long Beach, California. He won the Wimbledon mixed doubles championship with his sister, Tracy Austin, in 1980, becoming the first brother and sister team to win a Grand Slam title together.

John Austin reached a career high singles ranking of World No. 40. He now resides in Los Angeles with his son, Reed, and his wife, Karen. He is the brother of former professional tennis players Tracy, Pam, Jeff, and Doug Austin, and the brother-in-law of fitness expert Denise Austin.

Tracy Ann Austin Holt (born December 12, 1962) is an American former World No. 1 professional tennis player. She won three Grand Slam titles; the women's singles titles at the 1979 and 1981 US Opens, and the mixed doubles title at the Wimbledon Championships in 1980. Additionally, she won the WTA Tour Championships in 1980 and the year-ending Toyota Championships in 1981, both in singles.