Martina Hingis played in North America.
Hingis set a series of `` youngest-ever '' records during the 1990s , including youngest-ever Grand Slam champion and youngest-ever world No. 1.
The Grand Slam itinerary consists of the Australian Open in mid January , the French Open in May and June , Wimbledon in June and July , and the US Open in August and September.
The Grand Slam tournaments , also called majors , are the four most-important annual tennis events.
