The eighth-seeded Samsonova saved both break points she faced, while winning four of Collins' service games on Monday. Collins did herself no favours by double-faulting eight times.
Samsonova, the 24-year-old from Russia, is currently ranked world No.18. Her trophy on the hard courts of the US Open tune-up tournament a year ago was one of four singles titles she's won.
In other women's matches on day one at the first combined ATP-WTA 500 event, sixth-seeded Swiss Belinda Bencic advanced when Anastasia Potapova retired from their match in the first set, when trailing 5-6, with an injured left ankle.
Lauren Davis won the all-American clash against Sloane Stephens 7-6 (8-6) 3-6 6-1, while Marta Kostyuk eliminated 2019 US Open champion Bianca Andreescu of Canada 2-6 6-3 7-6 (7-5) in two hours 43 minutes.
"Honestly, I didn't believe I could win this one but I was just trying to play every point and stay in the match and fight not give up," said the 21-year-old Ukrainian.
Kostyuk will face No.2 seed Caroline Garcia in the second round.
In early men's action, Russia's Aslan Karatsev beat Kiwi Kiranpal Pannu 7-6 (7-3) 6-1, Alexander Shevchenko defeated Maxime Cressy 6-3 7-6 (10-8) and Michael Mmoh beat fellow American Bradley Klahn 6-3 6-3.
