Maria Sharapova eased into the second round of the US Open with a straight-sets win.
French Open champion and 2006 winner Sharapova, the fifth seed, won 10 straight games to prevail 6-4, 6-0 after falling 2-4 behind against her Russian compatriot and old friend Maria Kirilenko.
Elsewhere, the 43-year-old Kimiko Date-Krumm was beaten by 34-year-old Venus Williams 2-6, 6-3, 6-3.
Simona Halep, meanwhile, survived a scare in the tournament's first match on stadium court before overtaking Collins 6-7, 6-1, 6-2.
The 22-year-old Romanian, a French Open finalist, admitted to a bout of nerves in being thrust onto the big stage as the opening act of the season's last grand slam.
She moves on to face Slovakian Jana Cepelova, a 2-6, 7-5, 6-1 winner over Spain's Maria-Teresa Torro-Flor, in the second round of the season's last grand slam.
Also advancing on the women's side were fourth seed Agnieszka Radwanska of Poland, sixth-seed Angelique Kerber of Germany, and former world number one Jelena Jankovic of Serbia, the ninth-seed.