YOKOHAMA, Japan, July 25 (Reuters) - The gold-medal rematch the softball world had expected - and that Canada nearly intercepted - is happening after Japan set up a showdown with the United States. In Tokyo 2020"s two most thrilling games of softball yet, unbeaten sides the U.S. and Japan on Sunday separately won on extra-inning walk-off singles to earn spots in Tuesday"s final. United States and Japan will first square off on Monday in what will essentially be a dress rehearsal, with the loser batting first in the medal game. Meanwhile, Mexico homered their way to a 5-0 victory over a grim-looking Italy, which have not scored through four games. The winner of Monday"s Australia-Mexico game faces Canada for bronze the next day. In 2008, when softball last appeared in the Olympics, Japan ended United States" reign in the sport with a 3-1 win during a rain-interrupted final. Fittingly, Tuesday"s forecast calls for rain, and each team has their biggest 2008 stars on hand for the rematch. The Japan-U.S. duel, though, may not be good for softball"s prospects of returning to future Olympics. Critics say the lack of competition to the two teams makes for poor viewing. But Sunday"s action showed another side. Canada and Japan knotted 0-0 until the bottom of an extra inning, when veteran Eri Yamada slapped a single to centre field to bring home the lone run. Pitcher Danielle Lawrie, who came out of a seven-year retirement for the Games, delivered three shutout innings until Yamada"s hit left the Canadian speechless and several of her team mates covering tearful faces because they were out of gold contention. Earlier Sunday, United States, wearing red from hair ribbons down through pants, swarmed Amanda Chidester after her extra-inning single beat Australia 2-1. Tarni Stepto, Australia"s youngest player at 21, held U.S. batters to five hits over seven and 1/3 innings. Throwing nearly as fast as flamethrower and U.S. counterpart Monica Abbott, Stepto earned outs in key spots to keep the United States off the scoreboard until Chidester"s winning hit. "It was a lot of tense moments, but you live for these moments," Abbott said, raising her voice with excitement. "We live to be there and be able to step up for our team." Abbott, 35, who has competed professionally since Stepto was starting the sport as a six-year-old, twice ended bases loaded innings through strikeouts, with pitches whipping up like the 10 flags in centre field behind her. Abbott on an extra-inning walk allowed United States" only run so far in the tournament.