England's biggest mistake was to win the toss and decided to bowl first because in most of the matches the team batting first wins matches and England's captain decision of bowl first was a wrong one. England Bowled well and bowled Out Aus at 179. A total of under 180 run is an easy target. England top order and middle order failed they have not batted well, except Lemonstone, Other bastmen have not performed well and went out and all team bowled out at 151 runs. Australia's fast bowler spin bowling dangerous bowling and won the game quite easily.
Undoubtedly, England captain Philip Salt's decision was wrong and they proved it with their performance. After watching the results of the toss, I made a prediction that it was more difficult to score runs in the second innings than in the first innings at Southampton's venue, and England captain Philip Salt's decision was somewhat disappointing. In the end they failed to prove my prediction wrong and succeeded in proving their conclusion wrong.
I would blame England's match planning as the reason for England's loss in the first T20I vs Australia. I will not blame the performance of the players too much here, surely they could have performed better. If they could perform well, they would not depend on the field statistics. One thing is very important in cricket, if your match planning is not right, you cannot expect good results from your players. The outcome of the match and the performance of the players mostly depends on the match plan. I think the England team's match planning was very flawed and the team analyst has to take some of the blame.