Serena into Australian 4th Rd; dropped 9 total games so far

MELBOURNE, Australia (AP) — Serena Williams played clean and powerful tennis to overwhelm 18-year-old Dayana Yastremska of Ukraine 6-2, 6-1 and reach the Australian Open’s fourth round.
Williams grabbed a pair of service breaks and a 4-0 lead after less than 15 minutes Saturday.
Not only has Williams won every set she played this week — and 20 in a row at Melbourne Park, dating to the start of her 2017 run to the title — but she’s ceded a total of only nine games th