Megan Giglia won Great Britain's first medal of the XV Paralympics with gold at the Rio Velodrome on Thursday's opening day of action.
Giglia won gold in the C1-2-3 3km individual pursuit with a dominant performance.
The 31-year-old, who suffered a brain haemorrhage in January 2013, won the world title in Italy in March and took command once more in Rio.
Giglia also clocked a world record in qualifying in 4:03.544, more than eight seconds clear of the United States' Jamie Whitmore, her rival in the final.
"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 on 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."
Meanwhile Dame Sarah Storey won the 12th gold medal of her career to become Britain's most successful female Paralympian of all time.
Britain claimed a third medal in the velodrome as Steve Bate and his tandem pilot Adam Duggleby took gold the 4km pursuit.
Bate and Duggleby qualified quickest, in another world record.
Bate and Duggleby clocked 4:08.146 and met Holland's Vincent ter Schure and his pilot Timo Fransen in the final.
The Dutch pair clocked 4:09.527 in qualifying. And the British pair won in 4:08.631, Holland a distant second.
Another gold followed in the swimming pool as Ollie Hynd won Britain's fourth with victory in the S8 400m freestyle.
Hynd lowered his own world record to touch first in 4:21.89 and upgrade on the silver he won in London 2012.
"I don't think there has been a day where I have not thought about London and how disappointed I was not to get the gold so it makes it all worth it now," Hynd said.
"I'm so happy with the time. I wanted to go under 4:20 if I'm honest but a world record, I'm happy with that.
"I've worked so hard for that, I can't wait to get on the podium and get my medal."
Elsewhere on Thursday, a united Great Britain football team took on hosts Brazil.
Britain's seven-a-side footballers, for athletes with cerebral palsy or an acquired brain injury, lost 2-1 at the Deodoro Stadium.
The national Football Associations continue to block a British team at the Olympics, but there was no such issue at the Paralympics.
ParalympicsGB had three Scots and one Northern Irishman in the 14-man squad.
Former Birmingham player Jack Rutter captained a squad featuring ex-Liverpool player Sean Highdale and former Tranmere forward Ollie Nugent, who currently plays for Chester.
England captain Wayne Rooney sent the squad a good luck message prior to the tournament -- and it appeared they would need it in a tough Pool A also featuring Ireland and Ukraine, the Paralympic champions in 2004 and 2008.
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