Kin Cheung/Associated Press
MELBOURNE, Australia — Ann Chisholm contemplated traveling from her Minnesota home to watch the main-draw debut of her cousin Danielle Collins at the Australian Open, but it seemed like a flight of fancy. Collins had lost in the first round of the three majors she played last year, and it made little sense for a relative to travel 10,000 miles to see what might be only one match.
But Chisholm continued monitoring airfares after each of Collins’s first three matches in Melbourne, all victories. Then, in the fourth round, the unseeded Collins defeated Angelique Kerber, the 2016 champion and this year’s No.