A trio of former Grand Slam winners with seven majors between them powered ahead on the grass of Berlin, with local Angelique Kerber pacing the charge.
The champion at Australia, Wimbledon and the US Open defeated Misaki Doi 6-2, 6-1 while double Melbourne titleholder Victoria Azarenka defeated popular German Andrea Petkovic 7-6(3), 6-2.
Roland Garros and Wimbledon winner Garbine Muguruza put out Sorana Cirstea 6-3, 6-2 for a fourth defeat of the Romanian.
The Kerber win was special, as she had to save a match point against the Japanese in 2016 on the way to her first Grand Slam trophy in Melbourne.
“I had to turn that (first-round) match around, it is one I will never forget. It will always be on my mind.
“But today I was focusing on grass; she played well in the qualies and it can be dangerous against a lefty opponent who already has some matches on grass.
“I was just trying to play a good match today.”
Kerber, who has lost this season in first rounds in Australia and Paris, was happy to turn her attention to grass and the WImbledon run-up.
“It’s always tough playing the first of the season on grass, especially since we are back on it for the first time in two years.
“I”m happy with my performance and how I started the grass season.”
Azarenka took an hour and three-quarter to defeat Petkovic with eight aces and four breaks of serve.
Muguruza needed a bounce after a first-round loss at Roland Garros; she got it with six breaks of her 45th-ranked opponent’s serve.