With World Cup host city Volgograd gripped by a heatwave, Japan will aim to conserve energy and make the most of their substitutions in their final group-stage match against Poland, coach Akira Nishino said Wednesday.

Nishino said he had been surprised by conditions in the southwestern Russian city, where temperatures are forecast to hit 37 C by the time the pivotal Group H clash kicks off Thursday evening.

"When I landed yesterday, I was struck by how humid it was. It was probably more than I expected," Nishino said.

The 63-year-old said the weather would influence his planning for the match, in which Japan need one point to guarantee a knockout-stage berth.

"At the moment the players are switching well between defense and offense and our movement is very much coordinated and not (wasting energy). We need to keep this up, especially in the second half, when stamina (is most important)," he said.

(Nishino runs the rule over his players as they train on the eve of the Poland match in Volgograd)

"I think the Japanese players have good stamina, and given the likely match conditions, we'll need it. This is going to be a very important third match and our substitutions are going to be even more critical than in the previous matches."

Nishino said he would try to determine the impact on players of the heat, as well as their two earlier games -- a 2-1 win over Colombia and 2-2 draw with Senegal -- before picking his lineup.

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"Today, I don't think the team's physical condition is very much affected by (the heat), I think because we have had pretty good results so far," he said.

"But of course, perhaps everyone is tired, and given these hot and humid conditions, I will wait until after training tomorrow to confirm the starting 11," he said.

While Japanese players experience summertime soccer in high heat and humidity from a young age, the conditions in Volgograd will not necessarily give them an advantage, according to goalkeeper Eiji Kawashima.

"The conditions are the same for both teams. Of course we're very used to the heat, but whether we can control play in the heat is the crucial question," Kawashima said.

Though Japan are certain of advancing with a draw against Poland, they can still go through with a loss, provided Senegal beat Colombia in the other final group-stage match.

Poland have already been eliminated following losses to Senegal and Colombia.