Shinichi Shimakawa did not see Jim Roberts coming.

With Japan looking to close the gap on Great Britain in the third period of their wheelchair rugby semifinal, Shimakawa reached up to catch a pass.

Roberts arrived at almost the same time as the ball, and delivered a crushing hit that knocked Shimakawa off balance, knocked the ball loose and, more importantly, essentially knocked Japan out of contention for the gold medal at the Tokyo Paralympics.

Great Britain used a bruising defensive effort to seize control of the match in the second half and punch its ticket to the wheelchair rugby final with a 55-49 victory at Yoyogi National Stadium on Saturday.

“We knew that they had a long pass over the top and we wanted to completely stop that," Roberts said. "We wanted to make them push for every meter they had on our court, and the low-scoring game showed how we were able to do that."

Britain has never finished higher than fourth at the Paralympics and the nation’s first wheelchair rugby medal will be either gold or silver.

“We didn’t come here for second, we came here to do as well as we can and now that means gold," Roberts said. "We’ll be pushing as hard as we can tomorrow in that final.”

Great Britain will face the United States in the Paralympic final on Sunday. The Americans defeated Australia 49-42 in Saturday's other semifinal. Charles Aoki scored 27 tries for United States, which overcame a big night from Australian captain Ryley Batt, who had 25 tries and did all he could to keep his team in the match.

Japan will face Australia for bronze. The Japanese earned bronze at the Rio Games in 2016 and came into these Paralympics thinking of gold after winning the world title in 2018.

The Japanese, however, were not able to get past a stout British team.

"All the people have done their best to hold a Paralympics under the difficult COVID situation but we couldn’t meet the expectations of the Japanese people and that is the thing that I really feel sorry about," Japan's Daisuke Ikezaki said. "I wanted to delight them, but today that was all we could do. Great Britain were much stronger than us."

In a match that lived up to the sport’s reputation for violent collisions, Britain made the Japanese work for almost every try, as Japan had to battle through a blockade of defenders to put points on the board. The British were also able to come up with a few crucial steals.

The Britons, meanwhile, maneuvered around the Japanese for easy tries and led by two at halftime.

Britain blew the match open in the third period.

The British led by three when Roberts delivered his big hit and scored a try on their ensuing possession to take a 30-26 lead. It was all Great Britain from that point, as the British outscored Japan 17-10 in the period to take a commanding 42-33 lead into the fourth.

That rendered the closing stanza little more than a formality as Great Britain managed to close out the game even as Japan finally found a rhythm with the ball.

Britain finished with eight steals while Japan committed an uncharacteristic five turnovers.

Roberts finished with a game-high 20 tries and also had four steals. Aaron Phipps had 17 and Stuart Robinson finished with 12.

Daisuke Ikezaki led Japan with 13 tries while captain Yukinobu Ike had 10.