Harry Kane-inspired England will aim to seal their place in the knockout phase of the World Cup on Sunday while Japan bid to edge closer to a last 16 berth when they take on Senegal.
Victory for the Three Lions against minnows Panama in the heat of Nizhny Novgorod would send England through in Group G alongside free-scoring Belgium, who swatted aside Tunisia 5-2 on Saturday.
Booking their ticket to the second round with a game to spare would be a welcome achievement for England, who were eliminated after only two games in a disastrous 2014 World Cup campaign.
England opened in Russia with a 2-1 victory over Tunisia on Monday, Kane scoring twice including the winner in injury time to give Gareth Southgate's side a precious three points.
A similarly attritional contest could be on the cards on Sunday against the Central Americas who are making their World Cup debut.
While England are heavily favoured to take all three points, manager Southgate said Saturday there was no chance his team will be guilty of complacency.
"We've seen already the difficulty the big countries in terms of ranking have had in breaking down lower-ranked teams," cautioned Southgate.
England and Panama have a 3:00 pm kick-off (1200 GMT) in Nizhny Novgorod meaning players could struggle in temperatures topping 30 Celsius (86 Farenheit).
Dele Alli picked up a thigh strain in the 2-1 win against Tunisia and is likely to sit out with either Marcus Rashford or Ruben Loftus-Cheek coming in to a settled line-up led by captain Kane.
A win for England would see them head into a final group game against Belgium to determine who finishes top.
Belgium's Romelu Lukaku scored twice for the second game in succession Saturday, after the 3-0 win against Panama, to join Cristiano Ronaldo on four goals at the top of the race for the top scorer's Golden Boot.
Germany not safe yet
World Cup holders Germany were breathing a sigh of relief after Toni Kroos' 95th minute missile of a free kick secured a last-gasp 2-1 win over Sweden on a dramatic Saturday night in Sochi and meant they avoided a humiliating first-round exit.
But they are not out of the woods yet -- to have a chance of becoming the first team to successfully defend the title since Brazil in 1962, Germany must beat South Korea by a two-goal margin in Kazan on Wednesday. If they do not, their fate will be in the hands of the match between Mexico and Sweden.
Defender Mats Hummels said Kroos' goal could be a turning point.
"Something like this can be a big moment in the tournament.
"But if we lose against South Korea or don't make it to the next stage, the goal isn't worth anything."
Japan ready for Mane
In other games on Sunday, Japan can all but guarantee themselves a place in the second round if they follow up their surprise opening defeat of Colombia by beating Senegal in Group H.
The Asian giants have vowed to take an aggressive approach against Senegal, who are spearheaded by Liverpool forward Sadio Mane.
Japan coach Akira Nishino said his team planned to mark Mane closely in Yekaterinburg.
"I am sure we can deal with him but with the contribution that Mane can make, it might be possible to mark him one on one or even three on one," Nishino said.
"It is possible to stop him but the trouble is that he has influence too on other players, and that is what we are concerned about."
Nishino said he had encouraged his team to chase victory in the second half against Colombia in their first game, and would adopt a similar approach against Senegal.
"I always say the second match is the deciding match and we have to win, no matter who we play," he said.
"We need to earn maximum points. Even if it is slightly risky we want to attack and try to win."
Poland and Colombia round off the second round of group matches in the late game in Kazan (kick-off 1900 GMT), both knowing they dare not lose if the want to retain any realistic hope of progressing.
Colombia coach Jose Pekerman has hinted that 2014 Golden Boot winner James Rodriguez could start against the Poles, who were beaten by Senegal in their opening game.
Rodriguez has been bothered by a calf injury which meant he started on the bench against Japan, but Pekerman indicated he may be ready to face Poland.
"His appearance off the bench last time out gave him some confidence," Pekerman said.
"We've had to finetune a few little details, but he's been working hard in recent days and we're hoping he'll be 100 percent."