Brazil currently top Group D after securing two wins from two games, while Saudi Arabia have not registered a single point during this summer's tournament.
Match preview
Saudi Arabia have conceded five goals in their first two fixtures in Japan, meaning that their hopes of progressing into the quarter-finals diminished before the conclusion of the group stages.
Despite dominating possession against Germany Under-23s on Sunday, Saad Al-Shehri's side allowed the Germans to create more chances in front of goal and Stefan Kuntz's team capitalised on that.
Sami Al-Najei helped Saudi Arabia come from behind twice on the weekend, netting his first goals at the Tokyo Games, but even though Germany were reduced to 10 players when Amos Pieper was sent off after 67 minutes, they sealed a 3-2 win through Felix Uduokhai's strike.
That result means that Saudi Arabia's youngsters have not managed to surpass their previous best at an Olympics, when they were eliminated at the group stages in 1996 - with the senior team representing the nation prior to 1992.
Brazil have all but secured their place in the last eight with the four points that they have earned so far this summer, as they look to defend their Olympic Gold medal which they won at home in 2016.
After a Richarlison hat-trick and a late strike from Paulinho completed a victory against Germany in the opening round of games, Brazil had to settle for a goalless draw last time out when they faced Ivory Coast Under-23s.
Andre Jardine's side had to play the majority of the match against Ivory Coast one player down after Aston Villa's Douglas Luiz was shown a straight red card just 13 minutes into that game.
From there on in that fixture was a close contest with both teams creating chances on target, but the goalkeepers were on top and Aderbar Santos picked up his first clean sheet of the tournament.
Brazil have won a medal at the Olympic Games in the previous three tournaments and are one of the favourites to triumph in Tokyo, coming into this Olympics with an expectation to reach the final.
Everton striker Richarlison is currently second in the top-goalscorer table this summer, only one goal behind France's Andre-Pierre Gignac, and he will be looking to add to his tally on Wednesday against a team that has shown defensive frailties.
Saudi Arabia Under-23s Olympic Games Men's Football form:
Saudi Arabia Under-23s form (all competitions):
Brazil Under-23s Olympic Games Men's Football form:
Brazil Under-23s form (all competitions):
Team News
Saudi Arabia's Aboubacar Doumbia was shown a straight red card in the opening game against Ivory Coast, just five minutes after being substituted onto the pitch deep into stoppage time, and he will continue to serve his suspension on Wednesday.
Al-Shehri is likely to name the same starting 11 to the one that played against Germany on the weekend, after their performance would have pleased the manager and they were perhaps unlucky to not come away from that game with a point.
Attacking midfielder Al-Najei was a driving force in Saudi's performance on Sunday, coming up with a brace in that game, and he will be aiming for more goals in his side's final game at this summer's tournament.
Brazil have suspension issues of their own for Wednesday's clash after Luiz's dismissal against Ivory Coast - Gabriel Menino could replace Luiz in midfield and play next to Lyon's Bruno Guimaraes.
Jardine will want his side to top the group so despite already having one foot in the quarter-finals, the manager is likely to name a strong side to ensure top spot in Group D.
Saudi Arabia Under-23s possible starting lineup:
Al-Rubaie; Shahrani, Hindi, Amri, Abdulhamid; Al-Faraj, Al-Hassan; Al-Dawsari, Al-Najei, Khulaif; Hamddan
Brazil Under-23s possible starting lineup:
Santos; Arana, Carlos, Nino, Alves; Guimaraes, Menino; Claudinho, Cunha, Antony; Richarlison
We say: Saudi Arabia Under-23s 0-3 Brazil Under-23s
Brazil will want to build upon their clean sheet from their last outing and build a strong defensive foundation heading into the knockout rounds, meaning that it may be difficult for Saudi Arabia to find a way past Santos in goal.
After failing to score against Ivory Coast, Brazil and Richarlison will be hungry to get back onto the scoresheet, and after Saudi Arabia conceded three against Germany, Wednesday's opponents will look to capitalise on that weakness.