Honda's decisive contribution was handsome reward for Japan coach Takeshi Okada's gamble to deploy the CSKA Moscow midfielder in a central attacking role in an attempt to remedy his team's lack of goals. The Japanese, without a clean sheet in their warm-up matches, then frustrated Cameroon at the other end, surviving a late scare when the woodwork denied Stephane Mbia.
With the victory – their first in an opening game – Japan joined the Netherlands on three points at the top of Group E, while Cameroon's second match against Denmark, the day's other losers, assumes do-or-die dimensions.
The match began with a surprise in the Cameroon starting lineup with Mbia asked to fill in at right-back, his usual holding role in the middle going to Joel Matip. It was Cameroon's left-back Benoit Assou who was busier, though, with most of Japan's forward movement coming down their right side through Daisuke Matsui.
The Grenoble-based midfielder was the creator of Honda's winning goal when, after several crosses that came to nothing, he finally got his angles right and swung over a high ball which evaded the Cameroon defenders and fell at the far post to Honda. The CSKA Moscow man needed one touch to control the ball before steering it coolly past Hamidou Souleymanou.
Ironically Honda's strike came just moments after Cameroon had a shooting chance at the other end, when Eric Choupo Moting played a ball back to Enyong Enah but his low effort from the edge of the box went straight at Eiji Kawashima. There had been little end product up to then from the west Africans, despite their greater share of possession.
Samuel Eto'o, Cameroon's captain, had a quiet half, although the couple of occasions he did get on the ball brought the promise something might happen. The constant noise inside the stadium rose several notches when the Inter Milan forward delivered an early scare for Japan's defence after eight minutes, freeing Pierre Webo on the right side of the penalty box but his intended cutback to Choupo Moting was cleared.
Eto'o produced a flash of brilliance shortly after the restart when he span away from three blue shirts by the corner flag and teed up Choupo Moting for a shot that sailed over the far post. Cameroon were pushing Japan back and as night began to fall, and the temperature with it, coach Paul Le Guen looked to increase the pressure by sending on a fourth forward, Achille Emana, in place of Matip in the 63rd minute.
Webo got through but was offside, another Cameroon forward – Mahamadou Idrissou – entered the fray but still Japan absorbed the pressure. Indeed they might have had a second when Makoto Hasebe drew a low save from Souleymanou; substitute Shiniji Okazaki put the follow-up against the post but was offside. At the other end Mbia drove a shot against the crossbar but Japan – eight years to the day since their last FIFA World Cup victory – held on.