Croatia responded from their controversial World Cup opening loss to hosts Brazil with a 4-0 Group A defeat of 10-man Cameroon to keep their hopes of a place in the round of 16 alive.
The returning Mario Mandzukic scored twice -- and was struck by Cameroon midfielder Alex Song, who was sent off, late in the first half -- after earlier goals from Ivica Olic and Ivan Perisic.
Croatia believed they were the victims of an injustice when referee Yuichi Nishimura awarded hosts Brazil a controversial penalty in the tournament's opening game.
They swiftly put any lingering disappointment behind them in Manaus as Olic scored after 11 minutes against a Cameroon side previously beaten by Mexico and fighting to stay in the tournament.
The Indomitable Lions' task was soon tougher as Song was dismissed for lashing out at Mandzukic off the ball before the interval.
Having made an assiste on the opener with a fine pass, Perisic scored Croatia's second goal three minutes into the second half after a fine solo run and Mandzukic headed in a third before tapping in a fourth to complete a comfortable win.
Croatia play Mexico on Monday, June 23, with a place in the knockout stages at stake, while Cameroon are out ahead of their clash with Brazil.
Their frustrations appeared to boil over when Benoit Assou Ekotto and Benjamin Moukandjo had a dispute on the field, with the full-back perhaps fortunate to avoid a sending off for an apparent headbutt on his teammate.
Cameroon were without talisman Samuel Eto'o due to a knee injury, while Croatia had striker Mandzukic available again following his suspension for his dismissal in the playoff with Iceland last November.
Cameroon were soon behind when they failed to clear Darijo Srna's cross towards Mandzukic. Perisic had the composure to deliver a finely-weighted diagonal pass across the area for Olic to simply tap in.
Croatia took control of the contest and were given a numerical advantage when Song struck Mandzukic on the back as Croatia began an attack, with referee Pedro Proenca showing no hesitation in brandishing a red card.
Cameroon's woes deepened within three minutes of the restart as the impressive Perisic struck. Itandje's poor clearance found the Croatia midfielder, who surged down the left, outpacing the Cameroon defence, before executing a simple finish.
Mandzukic should have netted a third after being played in, but Nicolas Nkoulou applied enough pressure to put off the striker, who scooped his effort wide.
Half-time substitute Dany Nounkeu attempted a spectacular volley which flew well over as Cameroon tried to respond.
A Srna free-kick from the edge of the area went over before Danijel Pranjic's outswinging corner from the left was met by Mandzukic who was unchallenged as he headed the ball down and into the net.
Stephane Mbia shot narrowly over from long range before substitute Eduardo saw his shot saved weakly by goalkeeper Itandje. The ball was parried to Mandzukic who tapped in.
Moukandjo spurned the chance of a consolation with five minutes remaining, curling wide with the Croatia goal gaping.
Ivan Rakitic fluffed an opportunity for a fifth at the other end before Pierre Webo's header bounced up and clear off the bar following Assou Ekotto's cross.
Assou Ekotto and Moukandjo squabbled in the aftermath, with the former throwing his head towards his team-mate in the closing moments in an unsavoury conclusion to the contest.