However, there will be a sense of what-if for the tourists if they end up losing the five-test series 3-2.
"It would have been nice to have had a day like this at Edgbaston or Trent Bridge," Smith reflected. "I've never really seen a morning like Trent Bridge. I was pretty disappointed coming into this game.
"That's the way the game goes sometimes, you're not going to make runs every game. You just have to pick yourself up and keep trying to improve."
The 26-year-old did that by adopting a more conservative approach for the majority of his 394 minutes at the crease.
"I got a couple of decent balls but I was disappointed with my movements in the previous two test matches," Smith said. "I've tried to change that."
Smith started day two by facing 23 dot balls and moved from 96 to 100 with four singles. He shared a partnership of 146 runs with Adam Voges, then a 91-run stand with Mitchell Starc.
Smith became the leading run-scorer of the series and the first Australian since Matthew Elliott in 1997 to score 500 runs in an away Ashes.
Nathan Lyon started the rot when he ended the second session with a magnificent delivery that turned sharply and kissed the top of Alastair Cook's off stump.
Peter Siddle created the next two breakthroughs, Adam Lyth mistiming a pull shot and Ian Bell clean bowled by a pearler.
Mitchell Johnson removed Jonny Bairstow with a bouncer, while Mitch Marsh ran through the middle order, including the prized scalp of Joe Root.
"That is the best we have bowled all series," Smith said. "They created a lot of pressure."
There was a stretch of 32 balls where Australia didn't concede a run, while Johnson sent down a spell of three maidens.
Marsh snared 3-4 in 14 balls and was denied a fourth wicket when Mark Wood was recalled, replays revealing it was a no-ball.
Smith also earned a reprieve on 92 when Steve Finn overstepped.
"There is no excuse as a bowler," Finn said. "It's something for me to sort out."
- AAP
