Brazil's stuttering performance stemmed from anxiety at playing their first World Cup game, coach Tite said after their 1-1 draw with Switzerland in Group E on Sunday.
The five-time champions opened the scoring on 20 minutes when Philippe Coutinho's stunning strike went in off the far post but Steven Zuber levelled five minutes into the second half with a powerful header.
Switzerland were well-organised throughout and Brazil created chances but failed to convert them as Neymar and his team-mates lacked the guile to secure the win, becoming the latest of the tournament favourites to stumble.
Defending champions Germany lost to Mexico on Sunday while Argentina were held by Iceland and Spain drew with Portugal, with only France of the fancied teams winning despite an under-par display against Australia.
"Until we scored the goal there was a lot of pressure. There was a lot of anxiety, too much pressure and it translated into our way of playing, we were not precise enough," Tite told a news conference.
"We had some good, clean situations but could have been more precise. This kind of anxiety comes from the concern of playing a first game in a World Cup; even the coach is anxious."
As a result of those nerves, the Brazil defence were too passive when Zuber barely had to jump to head a corner home in the 50th minute, giving the Swiss a deserved point in a group also featuring Serbia and Costa Rica.
Brazil need to improve on dead balls, said Tite.
"In a World Cup, about 45 per cent of the goals come from set pieces," he explained.
His assistant, Cleber, rued the team's lack of killer instinct as Brazil enjoyed possession but too often lost the ball in or near the box. "The Swiss were more balanced than at the 2014 Word Cup, they put some pressure on us and we created chances but were not efficient," he said. Tite concluded: "Of course I'm not happy with the result. We wanted a victory. But anxiety hit us hard."
Brazil's next game is on Friday against Costa Rica, who lost 0-1 to Serbia in their opener.