The Hockeyroos rued their inability to land a decisive blow in a penalty-shootout loss to Belgium at Sydney Olympic Park, where thunderstorms halted the Pro League clash for almost an hour.
Australia scored a final-second equaliser then won a shootout 4-2 on Saturday against the same opposition, but the visitors prevailed on Sunday after finishing 1-1 in regular time.
Co-captain Jodie Kenny, gunning for her third Olympics, was the only Hockeyroo to convert as Belgium won 3-1 in the shootout.
"In actual game time, we should have won that - it's a frustrating game," Gabi Nance said, having scored in the final minute of the third term.
"We had great opportunities that we should have finished."
Learning how best to handle Tokyo's heat and humidity will form a key part of Australia's preparations for the 2020 Games, at which the Hockeyroos will be hunting their first Olympic medal since winning gold in 2000 at home.
A pre-Olympics acclimatisation camp will help but Sunday's sapping game has been an ideal lesson in adjusting to whatever Mother Nature produces.
The temperature soared above 36 degrees with high humidity, so officials extended the quarter-time break as per the sport's policy.
The contest, a scoreless draw at that stage despite Belgium doing all the attacking, stopped late in the second term because of concerns about nearby lightning.
The teams returned for the final 80 seconds of the opening half and the main break was reduced to just five minutes.
The Hockeyroos lifted after the interruption, with Nance's deftly deflected goal following 18-year-old Amy Lawton's scything foray forward.
"When we arrived, we were a bit surprised by how hot it was," Nance said.
"With 18 players on the bench, it makes it a bit easier, so you're just constantly rotating and ... you just try not to think about the heat too much.
"But the break actually helped us. We got our composure back ... but you don't want to rely on the weather.
"We just need to get a bit of a rocket a bit earlier; start harder and stronger than we did."
The hosts could easily have had another goal before three quarter-time, when Grace Stewart tapped in a loose ball that popped up in a goal-mouth scramble.
"It came off the keeper, so that's automatically a penalty corner," Nance said.
"But because she played on, we assumed it was play on. So once we played that shot, it should have been a goal."
Tiphaine Duquesne scored the equaliser in the 47th minute and found the net in the shootout.
Australian Associated Press