All the starting attackers are back after getting the day off against England on Thursday.
Belgium don't appear scared of what's ahead.
Striker Romelu Lukaku has claimed four with two against both Tunisia and Panama in the group stages. Given that no African team qualified either, it means they are still in position to reclaim their status as lovable underdogs. It could even be that this team now finally have the experience and confidence to take on anyone.
Belgium head coach Roberto Martinez left most of his first-choice footballers on the bench for the England match so they could rest and avoid suspensions for the Round-of-16 match.
Japan face an uphill task in their bid to win their first World Cup knockout match as they face high-flying Belgium in a Round of 16 match in Rostov-on-Don on Monday, July 2. Just ask holders Germany.
When it comes to big names, however, Belgium can put Japan in the shade.
"It will definitely be a hard match".
"We have a lot of respect for this team, and we don't think we are going to win this one easily". Following the way the group shook out, Senegal's football federation asked FIFA to reconsider the fair play rule as a tiebreaker. "We have nothing to lose". For Belgium, Eden Hazard, Romelu Lukaku and Kevin De Bruyne will be the big hitters and Japan would've liked to see them remain on the sidelines.
"The squad is in a very good place, mentally and physically", said Martinez.
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If they drew the match, the outcome of who finished first and second in Group G will be determined by their respective fair play records.
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And unlike teams like Argentina that struggled to find chemistry, Belgium have been a consistent unit throughout the past two weeks.
Now Japan stand in the path of another appearance in the quarter-finals, where Brazil or Mexico will lie in wait. This could be the year the country's golden generation finally come through and lift the trophy.
Lukaku scored the victor for Belgium in that friendly meeting last year, and Japan's Southampton centre-back Maya Yoshida knows from his time playing in the Premier League of the difficulties the 25-year-old striker will pose.
While Japan are beatable, there's no knowing which team will show up for Sunday's game.
Belgium, on the other hand, still have plenty to prove.
Vertonghen made amends for his mistake in the build-up to Japan's opening goal when his speculative header from out wide looped over Eiji Kawashima's grasp on 69 minutes. They know what it takes to win a game of this calibre.
Knowing that they would progress if the scores stayed the same - and as long as they didn't pick up any bookings - the Japanese just passed the ball around, with Poland quite content to let them do so. The players are aware that to be the best, they have to beat the best.
As mentioned earlier, Japan have done exceptionally well to get as far as they have. "I think there should be space for us behind the wings, or somewhere in that general area", said Inui after Saturday's training session.