Former Scotland under-20 international and Nottingham Rugby Club player Mitchell Todd was found in his car in a field near Normanton-on-the-Wolds in south Nottinghamshire last August.
An inquest into his death heard the 21-year-old's blood-alcohol reading was 172mg of alcohol per 100mls of blood. The legal driving limit is 80mg.
Empty bottles of wine and cans of beer were also found in the vehicle, the inquest at Nottingham Town Hall heard.
A post-mortem examination confirmed Todd, who represented Scotland under-20s in last season's Six Nations and featured in the Junior World Cup, died as a result of a catastrophic brain injury.
Resuming an inquest into the player's death, assistant deputy coroner Jane Gillespie heard Todd had drunk excessively after an all-day training event with Nottingham Rugby Club at Trent College in Long Eaton, Nottinghamshire, on August 14 last year before being found in his car in the early hours of the following morning.
Detective Constable Mark Henshaw, from Nottinghamshire Police, told the inquest the young player, who was described by his club as an exceptional talent, drank free wine and beer at a meal at the end of the training event.
He then got a taxi into Nottingham city centre where he continued to drink with his team mates until 2am.
The rugby club had warned players not to drive after the event at the college but Todd returned to his car.
The officer told the inquest it was not known why Todd, who lived in Coventry, had been driving on Cotgrave Road as he knew no-one in that area.
Residents in the area described hearing a loud thud at around 3.15am on August 15 and seeing a small, dark coloured vehicle travelling at speed.
Todd's mother, Delia Todd, wiped tears from her eyes as Police Constable Robert Lloyd, a forensics collision investigator, described the moments before the crash.
The officer told the hearing the Citroen had been travelling in excess of the 40mph speed limit when Todd lost control of his vehicle on a left hand bend.
He then drove on the wrong side of the road, clipping signs and trees as he careered across grass verges and kerbs before failing to take a right-hand bend and crashing through a fence and hedge into a field.
Mr Lloyd told the hearing the car was found to have no defects but that Todd had not been wearing his seatbelt.
He said: "If he had been wearing his seatbelt I think there would have been a very great difference to the outcome.
"He would have been shaken up but not have sustained the serious injuries he did."
Summing up the evidence, Ms Gillespie described Todd, who was born in Solihull and qualified for Scotland through his Edinburgh-born father, as a rugby player with a promising career in front of him.
Recording a verdict of accidental death, the coroner said: "This is a sad, unnecessary and preventable waste of a talented young life and I hope valuable lessons are learnt as a result of this tragedy.
"I find the combination of intoxication, excess speed and Mitchell's failure to wear a seatbelt resulted in this terrible incident and the catastrophic brain injury suffered by Mitchell, which he simply could not survive."
Nottingham Rugby chief executive Simon Beatham said: "The loss of Mitchell touched this club profoundly and our hearts, thoughts and sym-pathies are with all his family and friends."
Rob Brierley, Scottish Rugby Union's performance development manager, said: "Mitch was a quiet, sensitive bloke with a real steely determination.
"He was a real athlete, somebody who was late to the game and was developing all the time."