Samsonova won 25 of 29 (86%) first-service points as she continues her quest to earn back-to-back titles at the event, where she beat Kaia Kanepi (38) of Estonia 4-6, 6-3, 6-3 in the final a year ago.
It took just 59 minutes for Samsonova to oust Cirstea, who only managed to save one of five break points.
In two other second-round matches, number six seed Belinda Bencic (26) of Switzerland swept the United States' Lauren Davis (29) 6-1, 6-4, and Ukrainian Elina Svitolina (28) upset fifth-seeded Russian Daria Kasatkina (26) with a 6-2, 6-2 outing.
In a match between US countrywomen, third seed Coco Gauff (19) defeated Hailey Baptiste (21) 6-1, 6-4. Another match pitting two Americans concluded the evening's slate, with seventh-seeded Madison Keys (28) cruising to a 6-4, 6-0 victory over Jennifer Brady (28).
Livesport Prague Open
Indian Ankita Raina (30) spoiled Barbora Strycova's (37) home-court advantage by rallying from an early deficit to earn a 3-6, 6-3, 6-4 victory in a first-round match in the Czech Republic.
Strycova, a native of Pilsen, Czech Republic, tallied three aces and saved five of nine break points, but she let a 3-1, third-set lead slip away. Raina saved nine of 12 break points in advancing to the second round.
The day's other matches were both second-round affairs, with Jacqueline Cristian (25) of Romania cruising past Colombia's Emiliana Arango (22), 6-4, 6-3, and Ukraine's Kateryna Baindl (29) picking up a 5-0 win after German Jule Niemeier (23) retired in the first set.