Dame Sarah Storey began her quest to become Great Britain's most successful Paralympian by smashing her own world record in qualifying for the C5 3000m individual pursuit.
Defending champion Storey, who has 14 Paralympic gold medals – two fewer than swimmer Mike Kenny, emphasised her class by crossing the line in 3:27.057.
She will face compatriot Crystal Lane-Wright in the gold medal race later on Wednesday in a repeat of the Rio 2016 final.
Lane-Wright, who had to settle for silver in Brazil, finished in 3:35.061.
Storey was in dominant form from the off after being paired in the heats with New Zealand's Nicole Murray.
The 43-year-old, who is set to defend her C5 time trial and C4-5 road race crowns next week, shaved four seconds off her previous record, while Murray faded from a promising start to finish fourth fastest, allowing Wright-Lane another shot at gold.
Murray will face French rider Marie Patouillet for bronze.
Defending champion Steve Bate guaranteed three track cycling medals for ParalympicsGB on day one by progressing to the gold medal race of the 4000m individual pursuit.
The visually impaired rider was under pressure going into the final heat after Dutchman Tristan Bangma and pilot Patrick Bos set a new world record, becoming the first pair to go under four minutes in the event, finishing in 3:59.470.
Bate and pilot Adam Duggleby were unable to beat that time but their 4.02.497 was enough to hold off challenges from Poland's Marcin Polak and French rider Alexandre Lloveras and set up a final showdown with Bangma.
