Dame Sarah Storey has become Britain's most successful female Paralympian as ParalympicsGB swept to five gold medals on the first day of the Rio games.
The swimmer-turned-cyclist, 38, surpassed the record of former wheelchair racer Baroness Tanni Grey-Thompson by winning her 12th overall gold in the C5 3km individual pursuit at her seventh games.
British athletes took 11 medals of all colours on day one, with the first - a gold - won by Megan Giglia in the C1-2-3 3km individual pursuit cycling minutes before Dame Sarah's record-breaking win.
Dame Sarah, from Cheshire, who won her first two golds as a swimmer at the 1992 games in Barcelona, said: "Gold medal number 12. I never thought that was possible.
"After London everyone expected I might retire. Then I had a baby and everyone definitely thought I was going to retire.
"I've gone faster today. The gap to my opposition is bigger. I didn't expect that at all."
Dame Sarah's three-year-old daughter Louisa was present to witness her mother's victory, as was Baroness Grey-Thompson.
Swimmer Mike Kenny, with 16 golds, has the overall British record, which Baroness Grey-Thompson believes Dame Sarah can now take.
Baroness Grey-Thompson said: "I remember her as a skinny little 14-year-old in Barcelona, then she turned into a swimmer (with broad shoulders), now she's turned into a cyclist.
"I think she can do another games, it's whether the will and the drive is there. She won't want to do it half-heartedly.
"She was swimming when Mike Kenny was swimming. She knows Mike Kenny pretty well. I think she's got it in her. Go for it."
Dame Sarah qualified in a world record of 4 minutes 31.394 seconds - more than 17 seconds quicker than team-mate Crystal Lane.
Giglia also clocked a world record in qualifying of 4 minutes 3.544 seconds, more than eight seconds clear of American Jamie Whitmore, and she easily caught her rival in the final.
The 31-year-old, from Stratford upon Avon, who suffered a brain haemorrhage in January 2013, won the world title in Italy in March and put in a dominant performance in Rio.
Shortly after the two women's wins, Steve Bate and his tandem pilot Adam Duggleby won gold in the 4km pursuit.
Ollie Hynd added gold in the S8 400m freestyle in the swimming pool, before Bethany Firth won the S14 100m backstroke.
Hynd beat his own world record to touch first in 4 minutes 21.89 seconds and upgrade on the silver he won in London 2012. His brother Sam won the same event at the 2008 games in Beijing.
Crystal Lane won silver behind Dame Sarah, Harriet Lee claimed second place in the SB9 100m breaststroke and Jonathan Fox silver in the S7 100m backstroke.
Stephanie Millward took bronze in the S8 400m freestyle, Jessica-Jane Applegate was third behind Firth, and Andrew Mullen claimed third in the S5 200m freestyle behind Brazil's Daniel Dias.
Dias's 11th Paralympic title was met with a mighty roar from the partisan crowd as thousands of Brazil fans flocked to the games.
Britain must wait until day two for an athletics medal, but track and field could be profitable.
Jonnie Peacock made a statement as he launched his defence of the T44 100m title he won at London 2012.
The 23-year-old from Cambridge clocked a Paralympic record of 10.81 seconds in the amputee sprint, arguably the blue riband event of the Paralympics.
Brazil's Alan Oliveira did not even qualify for Friday night's final.
Georgina Hermitage advanced to the T37 100m final in a world record of 13.39 seconds, while Sophie Hahn was fastest, Kadeena Cox third fastest and Olivia Breen seventh as three Britons qualified for the T38 100m final.