It was a low-scoring day for Group F, with Morocco and Croatia tied and Belgium managing a solitary goal against Canada.
The action packed games in Group E more than made up for any excitement deficit.
In a surprise win, Japan emerged in tight match against Germany while Spain secured a high-scoring victory over Costa Rica.
Luka Modric's Croatia have made a frustrating start to the Qatar World Cup with the 2018 runners-up held to a goalless draw by stubborn Morocco.
Chances were sparse with Real Madrid's Modric among those coming closest in the opening match in Group F which also features Belgium and Canada who meet later in the day.
The Atlas Lions contained Croatia well for most of Wednesday's game but also failed to manage a breakthrough in Al Khor.
A long-distance attempt from Ivan Perisic went over the crossbar before Croatia came closest just before intermission, Nikola Vlasic denied by goalkeeper Yassine Bounou from close range after a fast move, and Modric then blazing high from the edge of the area.
The 37-year-old Modric and his team also lacked ideas in the second half and their goalkeeper Dominik Livakovic had to palm away a fierce but not very accurate free-kick from Paris Saint-Germain defender Achraf Hakimi in the 65th.
Late goals by Ritsu Doan and Takuma Asano have earned Japan an incredible 2-1 comeback victory over Germany.
The four-time champions had looked to be cruising to victory on Wednesday via an Ilkay Gundogan penalty but paid a fatal price for missing chances.
The shock result was a repeat of their 2018 World Cup nightmare when, as defending champions, they lost their opener to Mexico and, after another defeat by South Korea, were condemned to a group-stage exit.
"This is a huge disappointment and frustrating," Germany captain Manuel Neuer said. "We made the opponent strong. The final desire made the difference. Japan believed they could win while we thought we could preserve the lead."
Coach Hansi Flick said: "It is brutally disappointing. We are annoyed we lost the game because we had the chances. We have to look forward. We have the chance for six points".
Having seized hold of the match with a goal inside a dozen minutes La Roja made sure not to let go.
By the half-hour they were 3-0 up with New Zealand's playoff conquerors reduced to trying to keep the score down.
That they failed to do, Spain adding another four in the second half.
The seven-goal victory was not even flattering such was Spain's superiority, Costa Rica failing to manage either a shot or a corner.
"When things go your way like this, soccer becomes wonderful," Spanish coach Luis Enrique said. "We played exceptionally well with and without the ball."
IN OTHER NEWS:
Michy Batshuayi has scored in the first half and Thibaut Courtois saved a penalty as Belgium opened their World Cup campaign with a scrappy 1-0 win over an energetic Canada.
Leading the Belgian attack in the absence of injured talisman Romelu Lukaku, Batshuayi scored on the stroke of halftime to put the Red Devils top of Group F ahead of Morocco and Croatia who earlier drew 0-0.
In their only previous World Cup appearance, in Mexico in 1986, Canada lost all three matches and failed to score.
They looked as if they would register their long-awaited first goal when Belgium's Yannick Carrasco handled the ball in the 11th minute and Alphonso Davies stepped up to take the penalty.
But Courtois, one of the world's best goalkeepers, denied him by stopping his weak spot-kick.
- with Australian Associated Press
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