By JOHN PYE
AP Sports Writer
MELBOURNE, Australia (AP) — Stefanos Tsitsipas maintained his perfect record in Grand Slam quarterfinals with a straight-sets win over No. 11-seeded Jannik Sinner to reach the last four of the Australian Open. Seventh-seeded Iga Swiatek rallied to beat 36-year-old Kaia Kanepi 4-6, 7-6 (2), 6-3 and move into the women’s semifinals against Danielle Collins. The 2020 French Open winner took 3 hours in temperatures reaching 36 degrees Celsius (97 degrees Fahrenheit) to secure her spot in the final four. Collins had a 7-5, 6-1 victory over Alize Cornet in the opening match on Day 10. She joins fellow American Madison Keys in Thursday’s semifinals. Keys will play top-ranked Ash Barty for a spot in the Australian Open final.