Fresh from her triumph at SW19 earlier this month, Barty started her adventure alongside long-time friend Sanders for Australia.
The No.6 seeds hammered Japan pair Nao Hibino and Makoto Ninomiya 6-1 6-2.
"Playing with my childhood friend in what is a dream for both of us is really cool. And to be here in some of the most unique circumstances I think ever for an Olympic Games, it's really awesome for us," Barty said.
"We're very grateful and thankful that we're able to be here to play and to experience what is really cool Games."
Iga Swiatek, meanwhile, believes adjusting to the tricky Tokyo conditions will be key to winning gold after she came through her Olympics opener on Saturday.
The Polish athlete was the highest-ranked seed in action in the women's singles in the Japanese capital and comfortably dispatched of Mona Barthel 6-2 6-2.
Swiatek was on court for a little over an hour, breaking serve six times and firing down 13 winners to Barthel's eight.
The tough hot and humid conditions were a big talking point at Ariake Tennis Centre on Saturday, and Swiatek – whose father represented Poland as a rower at the 1988 Seoul Olympic Games – had her say.
"I'm pretty happy that I'm into the second round and for sure not only the temperature was hard, but also the sun because on one side it was pretty hard to serve," she said.
"But we had to adjust quickly and change our toss, so that was hard, but you know I would say the players who can adjust quicker are going to be the best ones here."
No.8 seed Barbora Krejcikova was 5-2 up against Zarina Diyas before her opponent had to withdraw with an ankle problem. The Czech now meets Leylah Annie Fernandez in the second round.
Fellow seeds Belinda Bencic (9), Anastasia Pavlyuchenkova (13), Maria Sakkari (14) and Elena Rybakina (15) all made it through round one.
Kiki Bertens, the No.16 seed, was not so lucky, sent packing 6-4 3-6 6-4 by Marketa Vondrousova.