Wade hit a career-best 75 while Clarke also scored 75.
Mike Hussey smashed 49 from 37 balls before he was out in the 50th over.
"We prepared for wickets that were going to spin a lot," Starc said.
"The quicks took nine of our wickets so the fast bowlers are going to play a massive part as well as the spinners in these conditions."
Afghanistan recovered from a shaky start at 4-49 as Mohammad Nabi (46) shared an 86-run stand with Asghar Stanikzai (66).
Afghanistan's bold run chase suffered a setback when Nabi was bowled by Johnson. It took a brilliant diving catch from Clarke at mid-wicket off the bowling of Starc to dismiss Stanikzai, who had been cramping badly, at 6-165.
The match began at 6pm and went beyond 1.30am to avoid the heat, in the first ODI scheduled to be played over two days. However at midnight the temperature was still 34 with a humidity of 63 per cent.
Debutant Glenn Maxwell (two) was the only batsmen in Australia's top seven not to get a start.
Clarke was his usual stylish self and led from the front, hitting three fours and two sixes in his 94-ball knock.
Starc said the Australians had been keen to show improvement on last month's 4-0 series defeat against England.
"We spoke about our batting. There was a lot of talk from that England series and in the last couple of weeks," Starc said.
"So we wanted to come out and stop talking and put actions on the board.
"We did that tonight. Our batters batted quite well in the heat.
"Tonight the fast bowlers, we all bowled quite well. I reckon we executed our plans pretty close to how we wanted to."
Frontline spinner Xavier Doherty claimed 1-34 while Maxwell, David Hussey and Clarke bowled nine overs for 35 runs.
- AAP