Lutalo Gilkes, 30, works as a patient access specialist at The Royal Orthopaedic Hospital in Northfield, Birmingham.
He was at home in Birmingham city centre when BOTB presenter Christian Williams turned up to give him the good news.
Knowing who Christian was straight away, Lutalo said: "Have I actually won the dream car?"
Arsenal fan Lutalo explained he was a long-time Audi lover and used to drive an A3.
"I thought the RS model was out of reach for me, until now," he said.
"It’s my actual dream car and I’ve been playing the BOTB competition for years to try and win it."
He added: "I don’t actually have a car at the moment and have been saving up for one - what perfect timing.
"This is the best day ever, what more could I ask for?"
Lutalo said he’d spend the money on his upcoming holiday to Greece as well as to treat his girlfriend, Katie.
BOTB hands over the keys to two cars each week as well as a lifestyle prize and has given away more than £47 million worth of cars so far.
The company uses former professional footballers to judge the competition independently, alongside current and former referees.
BOTB’s Christian, who surprises winners every week, was thrilled to give Lutalo the good news:
"The Audi RS3 paired with the £20,000 cash makes for a fantastic win and I’m super excited for Lutalo to get behind the wheel of his new car. "Massive congratulations again Lutalo."