The all-rounder went on to punish Afghanistan in remarkable fashion with 201 not out, the 35-year-old finishing the match with his 10th six as he became just the third batsman after New Zealand's Martin Guptill and West Indies' Chris Gayle to score a World Cup double hundred.
"To give a person like Maxwell a chance, he's going to run with it," said Trott.
"When you get an opportunity against a side like Australia, you've got to grab it. They're not going to just give it to you."
'Phenomenal'
Nevertheless, the 42-year-old former England batsman was in no doubt about the quality of Maxwell's innings.
"Full credit to him, the way that he played to get a double hundred is phenomenal," said Trott.
"He deserved to win the game; he got a double hundred...Sometimes you've got to take a cap off to a person the way that he played, but he shouldn't have been allowed to play like that. We should have had him out earlier."
Victory would have seen Afghanistan take a giant stride towards the semi-finals, with this result instead seeing Australia into the last four.
"We've all enjoyed the victories," said Trott, adding: "I said we win as a side and make sure we lose as a side. There's no pointing fingers."
One consolation on a chastening night was that Ibrahim Zadran became the first Afghanistan batsman to score a World Cup hundred, the opener's 129 not out the centrepiece of a total of 291-5.
"To get that first hundred (in a World Cup) was fantastic," said Trott.
"Maybe there's times where he could have accelerated a little bit quicker, but he's a fantastic player and a great lad. So, I'm really happy for him and hopefully many more (hundreds)."
Afghanistan head into their concluding group game, against Trott's native South Africa, in Ahmedabad on Friday still with a mathematical chance of reaching the last four.
But they will still need other results to go their way even if they defeat a Proteas side who've already qualified for the semi-finals.
"We lost the New Zealand game, came back and won the next game," said Trott. "We lost the India game very heavily but came back and beat England."
He added: "There's no time to muck around, we've got to pick ourselves up and learn from the experience. But it's a bitter pill to swallow.
"It would really be nice sitting here with 10 points. But hopefully that's after the South Africa game."