The 63-year-old, who took charge last month from Vahid Halilhodzic, attempted to take the pressure off his players ahead of their warm-up game with Ghana in Yokohama on Wednesday.

"The final 23 players won't be decided by one game," Nishino said.

"At this stage of course I have a general idea but I have to plan for what happens in the case of injuries," added the former Japan Football Association technical director, who names his squad for Russia on Thursday.

"Right up until the morning after the Ghana game, I have to think about all sorts of eventualities - I'm sure the doubt and anguish will continue."

The 23-year-old striker has already racked up 23 goals for IR Iran since making his debut against Montenegro in May 2014. 

That has put him in the top five of Team Melli's all-time goalscorers, helped by his great leaping ability and bursts of acceleration.

Born in the remote city of Gonbad-e Kavus in northeastern Iran, Azmoun was a volleyball star in his teenage years before landing a place at the Sepahan football academy in Isfahan.

He made a serious impact with IR Iran's youth teams between 2009 and 2013 and was snapped up by Russian club Rubin Kazan at the age of 17, becoming the first Iranian to play in the Russian Premier League. 

Azmoun stayed with the team despite reported interest from Arsenal and Liverpool, among others. He left for Russia's Rostov in 2015 before returning to Rubin Kazan two years later.

Kim, 28, was one of five players who played the full match in Korea Republic's 2-0 win over Honduras at Daegu Stadium on Monday. It was his first international match since January.

"I joined the national team with a mindset that I need to be alert at all times," Kim said. "Instead of saying we played good defence against Honduras, I want to say it was fortunate for us to have a clean sheet."

The friendly against Bosnia and Herzegovina in Jeonju on Friday will be Korea Republic's last tuneup match at home before they fly to Austria on Sunday to set up their pre-2018 FIFA World Cup Russia camp.

Saudi Arabia made their World Cup bow in 1994 in the United States, and have only missed out on two editions since then, namely South Africa 2010 and Brazil 2014. Here are the top three highlights of their four World Cup campaigns.

Ever since making their debut at the 1998 FIFA World Cup in France, Japan have experienced many highs and lows over the years. Here are some of their best moments on the global stage in the five tournaments they have featured in since then:

The friendly was part of Saudi Arabia's preparations for the 2018 FIFA World Cup Russia, where they will face hosts Russia in the tournament opener on June 14.

Saudi Arabia coach Juan Antonio Pizzi was pleased with his team's performance despite the defeat.

"In the second half we held our own against one of the best teams in the world," said Pizzi. "Although they are not in the World Cup, they have a great coach, an unparalleled history."

The FIFA World Cup is without a doubt the grandest stage in world football, and it comes as no surprise that a strong showing at just one tournament could massively shape a player's career in the years to come. As such, here are a number of players that could possibly propel themselves into the spotlight when the tournament kicks off in just over two weeks' time.