MELBOURNE, Australia — In 2020, Iga Swiatek won her first Grand Slam title at 19. The following year, Emma Raducanu won her first Grand Slam title at 18. The pair of teenage major winners have followed divergent paths since then. Swiatek has added four more Grand Slam titles to her tally, spending over 100 weeks as world No. 1 in the process; Raducanu hasn’t reached the final of a single WTA Tour event, even less another major. Their Australian Open third-round match on Saturday is one of the mo