Norfolk has now won 41 career singles titles since 2001
Britain's Peter Norfolk won his fourth Australian Open quad wheelchair singles by beating David Wagner 6-2 7-6 (7-4).
It was his 17th major title and the 41st singles title of his career and ensured he stayed as world number one.
Norfolk, 49, the first Briton to win a Paralympic tennis medal with singles gold in Athens in 2004, kept his title and won doubles bronze in Beijing.
"It's a great achievement to win my fourth Aussie Open and I am really happy with today's win," he said.
Norfolk added: "I am also happy with the way my team has worked this week and to be in the sunshine, not the snow.
"I love repeats and to do it in straight sets is very satisfying. I hope to have set the stage for Andy Murray on Sunday.
"It's nice to consolidate my number one world ranking this early in the season, especially with the support I have had this week from Andy, his mum and Team Murray, not to mention the support from Roger Draper, who watched every one of my matches."
Norfolk quickly opened up a 4-1 lead in the first set and sealed it with his first set point.
The Hampshire player led 3-1 in the second set but the American then won four games in a row to lead 5-3.
But Norfolk forced a tie-break in which he moved 4-1 ahead and although Wagner levelled at 4-4, Norfolk took the next three points to wrap up victory in one hour and 36 minutes.