Warwickshire's Megan Geglia rode to Paralympic gold with a superb victory in the C1-2-3 3km individual pursuit.
Giglia had qualified with a world record time of 4.03.533 and took on American Jamie Whitmore in the final.
The 31 year old was close to Whitmore at the halfway stage and she passed the American to take the gold medal.
"To be fair it hasn't sunk in yet, all I know is I wouldn't be here without my team, the back up crew behind me here, my family and friends," Giglia said to Channel 4.
"I only look forward to the future. I didn't think I would make it to Rio, I thought it was a bit ambitious but I thought I would give it a go.
"Within the British camp the atmosphere is great, everyone is hyped up and ready to go.
"I hope this will be the first of many golds. I've still got three events to go so we'll have to see.
"I've got my main event out of the way now so I can just enjoy the rest of them with my legs pedalling fast."
Dame Sarah Storey won her 12th Paralympic gold medal winning the C5 three-kilometres individual pursuit.
Storey met fellow Brit Cystal Lane in the final and had caught her in less than a hundred seconds to take gold.