Cardiff Crown Court heard Vincent Hamlyn was seen "jostling for pole position" in a "form of race" before the crash.
Kevin Morgan, 60, died after colliding with Dr Hamlyn's BMW Z4 on the A449 in Newport on 21 June, 2014.
Dr Hamlyn, 33, an anaesthetist from Chepstow, Monmouthshire, denies causing death by dangerous driving.
The court heard Dr Hamlyn told police in an interview: "There was no intention to race anyone."
He added:  "I would not say I headed towards the carriageway aggressively, but it was swiftly, I headed off as I normally would toward an open 70 mph road."
Mr Morgan, from Cwmbran, Torfaen, died from "catastrophic" head injuries, the court heard.
The prosecution claims both men had been "gunning" their engines at traffic lights, before speeding off in a race.
The trial continues.
A driver accused of causing a motorcyclist's death had no intention of racing him, a jury has been told.