Sarah Storey put in another world record-breaking performance on her way to claiming her 15th Paralympic title - Britain's first gold of Tokyo 2020.

She smashed her world best by over four seconds in the C5 3,000m individual pursuit qualifying and caught team-mate Crystal Lane-Wright in the final.

The 43-year-old is just one behind Mike Kenny's British record of 16 golds.

There was also silver for tandem pair Steve Bate and Adam Duggleby in the B 4,000m pursuit.

Bate and Duggleby were defending champions but the Dutch pair of Tristan Bangma and Patrick Bos, who set a world record in qualifying, caught the Britons in the final.

The opening day of action at the Izu Velodrome belonged to Storey though. She started the final in determined fashion and caught Lane-Wright after 1,750m of their race.

She has now won medals at each of the eight Games she has attended and her heat time of three minutes 27.057 seconds destroyed the world record she set in Rio.

"It's quite overwhelming," she said. "I don't know if it will sink in until I get home. I came here with a really solid plan of what I wanted to do and I've delivered it, so it kind of blows your mind a bit.

"I talked before about breaking your personal best, in my case a world record, a small margin at a time. And I just knocked 4.3 seconds off.

"I've done so much training, and everyone's been reminding me how much work I've done and how I deserve to be that fast, but you don't like to presume. So it took me by surprise, but a good surprise.

"I think about one race at a time and maybe I'll think about these things afterwards. But it does feel pretty surreal."

Storey, who was born without a fully functioning left hand, started her career as a swimmer at Barcelona in 1992 and competed at four Games, winning 15 Paralympic medals, including five golds, before switching to cycling in 2005.

Since then, the mother of Louisa (8) and Charlie (3) has been almost unbeatable both on the track and the road.

"I knew I had it in me to go sub 3.30," she added. "It's been a target of mine since I went 3.32 at the London Games. I knew I just needed the right day and the right preparation.

"It's been an incredibly difficult preparation for these Games because it's so different to what I'm used to. I just had to call on all my experience for staying calm under the pressure and I'm just glad it's paid off.

"It's fantastic to see the event getting faster, and I just need to keep getting faster as well. So I just had to keep a cool head."

She next goes on Tuesday in the C5 road time trial - another event where she is defending champion - before the road race on Thursday, 2 September.

For Lane-Wright, who also set a personal best in the heats, it is the second silver medal at consecutive Games in the event.

"I don't think I've reached my full potential. I think I can keep getting better," she said. "As much as I'm up against Sarah, it's me against me. I can only control what I can do. To get such a good PB this morning, I'm so pleased."