Japan edged out Cameroon in a dour encounter at Bloemfontein's Free State Stadium which produced little in the way of goalmouth action.
A far from capacity crowd witnessed two out-of-form teams struggle to find any inspiration in another tepid World Cup encounter.
After a dire opening half-hour Japan took the lead against the run of play when Dalsuke Matsui's cross looped over Stephane Mbia and was met by Keisuke Honda, who fired in coolly at the back post.
Japan almost doubled the lead when Makoto Hasebe crashed an effort towards goal but it was well saved by Souleymanou Hamidou before the offside Shinji Okazaki clattered the post as he followed up.
Cameroon finally found some urgency in the closing stages as Mbia rattled the crossbar from 25 yards but the well-drilled Japan side were able to hold on and go level with the Netherlands at the top of Group E.
The Blue Samurai, who had lost four straight games in their World Cup build-up before drawing 0-0 with Zimbabwe, set out so defensively it seemed they would be happy with a point from the opening whistle.
And although Cameroon showed more endeavour, the fact that star striker Samuel Eto'o was played wide on the right and was often found lurking very deep meant they lacked any sort of cutting edge.
A 37th-minute shot from Eyong Enoh was the first goalmouth action of the game and, although it was comfortably collected by Japan goalkeeper Eiji Kawashima, it did finally suggest Cameroon may start to find gaps in the Japanese defence.
But the opposite was true as, despite their lack of attacking intent, Japan took a surprise lead one minute later.
Matsui's deep left-footed cross was completely missed by the Cameroon defenders and Honda had time to control the ball before passing into the net.
The Indomitable Lions are the most successful African side in World Cup history having qualified for the World Cup six times, but the pride and passion shown by previous incarnations was sadly lacking in this first tournament on their own continent.
Only one brief moment of class immediately after half time suggested Cameroon might rouse themselves from their slumber.
Three-time African Footballer of the Year Eto'o finally showed a glimpse of his ability when he picked the ball up on the right and beat two men on his way into the area before squaring to Maxim Choupo-Moting but the striker could not control his finish and blasted over the bar.
But that impetus was not to last and it was not until the 85th minute that Cameroon found two efforts which could have stolen them a point.
In a moment of inspiration totally out keeping with the rest of the game, Mbia hammered a stunning effort towards goal from 25 yards which crashed off the crossbar and following that Kawashima saved from Pierre Webo in injury time.
In fairness to Japan the Asian side's tactics worked almost perfectly as they defended solidly but on this evidence the Netherlands and Denmark will have little to worry about going into the tournament's second week.
Attempts on target
Attempts off target
Projected table based on current scores
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|Group E teams||P||W||D||L||F||A||GD||PTS|
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|Group G teams||P||W||D||L||F||A||GD||PTS|