If there are a number of question marks against Takeshi Okada's Japan side going into this FIFA World Cup, one stands out above all others ahead of their opening Group E game against Cameroon – namely, how to stop Samuel Eto'o.

Cameroon's captain enters the tournament on the back of making history as the first man to win back-to-back trebles in European football, first with Barcelona in 2009 and then Inter Milan last month. The 29-year-old striker hit nine goals in eleven outings in qualifying for South Africa and his national coach, Paul Le Guen, described him as "an iconic figure" on the eve of the match in Maungang/Bloemfontein.

Not surprisingly, Eto'o was also the main talking point when Japan coach Okada sat down to face the press at the Free State Stadium. Okada admitted that his team were up against a special talent but added that Eto'o was by no means the Indomitable Lions' only threat. "Eto'o is the most important player but Cameroon are not only Eto'o, they have other players in their attack like [Achille] Emana and [Pierre] Webo, who are talented forwards in their own right," said the coach, who led Japan into their first FIFA World Cup in 1998.

“We cannot focus only on Eto'o but as far as he is concerned, our players do need to be well-briefed on his qualities and how he plays. We don't want just one single player man-marking him but to watch him as a unit,” added Okada. The fact Japan have shipped nine goals in losing their last four friendly games is likely to give further encouragement to Eto'o, who is expected to start in a front three for Cameroon alongside Eric Choupo Moting and Webo.

Eto'o is the most important player

Japan coach Takeshi Okada

That said, Okada has plans in place to try to limit the supply line to the Inter man. Right winger Daisuke Matsui, who has considerable experience of facing West African footballers after six years in France, will be asked to lend support to the full-back behind him in an attempt to stop Benoit Assou-Ekotto getting forward and putting balls into the box – something Okada has identified as a source of danger in Cameroon's play. The spotlight will be on other Japan players too. Okada only confirmed Eiji Kawashima as his first-choice goalkeeper after his impressive display against England at the end of May, while Yuichi Komano is likely to be thrown in at right-back behind Matsui because of the fitness doubts surrounding Yasuyuki Konno.

For all the threat Eto'o brings, though, Okoda does not want Japan to focus only on defence. "I've never told the players to concentrate on defence against Cameroon – we should be proactive, pass the ball well and keep trying to do that," he said. "We will be positive in our attacking too." How positive remains to be seen, though, given the Japanese have scored only once in their four warm-up games – when Marcus Tulio Tanaka converted a set-piece against England. Okada is prepared to gamble to find a solution, hence the anticipated selection as a lone striker of CSKA Moscow midfielder Keisuke Honda, who – despite no previous experience there – filled the role in the first 30 minutes of the training game against Zimbabwe last week.

Okada added: "Goals are always an issue for every team and it is also the case for us – set-plays, counterattacks, we've been working constantly on how to get goals in the competition." The hope for Japan fans is their favourites do not get a lesson in scoring them from Eto'o. The Cameroon No9 had reportedly been unhappy with comments made by Roger Milla, his country's 1990 FIFA World Cup icon, criticising his contribution to the national team. According to Le Guen, however, Eto'o's focus is "on the really important things". Which could spell bad news for Japan.