New York - Ana Ivanovic has kept her hot streak rolling with a straight-set victory to start the US Open.
The eighth-seeded Serb beat American Alison Riske 6-3, 6-0 in the first round Tuesday.
Ivanovic has won 48 matches this year, more than anyone else on tour.
The 2008 French Open champion has struggled to get back to that level but finally seems to be inching closer.
She returned to the top 10 this month for the first time in more than five years.
Ivanovic was broken in the first game Tuesday but quickly took control.
The 24-year-old Riske made a breakthrough at last year's US Open, reaching the fourth round after an upset of Petra Kvitova.
She reached a career-high ranking of No. 40 this summer.
Results on Tuesday from the second day of the US Open, the final Grand Slam tournament of 2014 (x denotes seeded player):
Mona Barthel (GER) bt Zhang Shuai (CHN x32) 6-1, 6-2
Samantha Stosur (AUS x24) bt Lauren Davis (USA) 6-1, 6-4
Casey Dellacqua (AUS x29) bt Patricia Mayr-Achleitner (AUT) 7-5, 6-3
Wang Qiang (CHN) bt Paula Kania (POL) 6-2, 6-0
Karolina Pliskova (CZE) bt Yvonne Meusburger (AUT) 6-2, 6-2
Ana Ivanovic (SRB x8) bt Alison Riske (USA) 6-3, 6-0
Sorana Cirstea (ROM) bt Heather Watson (GBR) 6-1, 6-1