Aneurin Donald admitted he was unaware he was smashing records as he blasted 234 in an incredible innings for Glamorgan on Sunday.

The 19-year-old underlined his rich promise by scoring the joint fastest double century in the history of first-class cricket against Derbyshire at Colwyn Bay.

He also managed to dent five cars in the car park with a succession of huge sixes.

Donald took just 123 balls to reach 200, equalling Ravi Shastri’s record and his whole innings was compiled from just 136 balls.

Coming in at 96-3, the teenager tipped for a big future with England, hit 15 sixes and 26 fours before he was dismissed on the way to Glamorgan reaching 481 for 1 on the opening day of their Specsavers County Championship match.

Donald’s astonishing knock was made from the identical number of deliveries as Shastri’s innings from 1985, but Donald required just 43 deliveries for his second hundred.

He also became the youngest double-centurion in Glamorgan history – five years younger than the previous incumbent John Hopkins.

But he said: “I had no idea of the records that went, but it was especially pleasing to equal Ravi Shastri’s previous record, as he is also a former Glamorgan player.

“I was pleased because it has put the team in a strong position, and after a lean patch recently, I was delighted to get a big one.

“It’s nice to get the guys into a strong position first and foremost, but nice to hit them so well and come out with a big score. I’ve been looking for one and finally it came, although I rode my luck at times.

“It was a good wicket, the bowlers were getting a bit tired and it’s a small ground, so it’s about making the most of it. I knew the highest score was here [Glamorgan’s record of 309 not out by Steve James] so obviously there’s a good history.

“It’s a good place to be [in the six-hitting zone], you don’t get there too often, you end up not thinking about it too much and it flows.

“You don’t get too many days like this and it was nice to make the most of it. I didn’t know [about the fastest all-time double-century] until I walked off. I would have tried to get it a bit earlier.”

Donald did not appear until 2.10pm but was soon into his stride and was particularly severe on the young leg spinner Matt Critchley who was struck for 24 in one over.

He added 115 with Bragg and later 130 in 15 overs with Craig Meschede.