0118 GMT December 02, 2021
The Olympic host needs to beat group leader Denmark on Wednesday to avoid a stunning exit, just two years after their devastating 7-1 World Cup defeat by Germany, AFP reported.
Neymar was expected to ease Brazilian football's wounded pride by delivering a first ever Olympic gold for the five-time world champion.
However, the Barcelona star was eclipsed. And just as in its opening stalemate against South Africa, Brazil was booed from the field in Brasilia on Sunday as its players paid for their profligacy in front of goal.
Portugal and Nigeria were the first sides to seal their places in the quarterfinals with victories over Honduras and Sweden respectively.
There were also wins for Argentina, Denmark and Mexico.
In contrast to his display against South Africa when he was labeled "greedy", Neymar was a peripheral figure against Iraq and lost his cool when he fired the ball at Sherko Kareem in the second-half as the Iraqi prevented him from taking a quick free-kick.
Manchester City's £27 million ($36 million) signing Gabriel Jesus had another night to forget. After claiming he "wouldn't sleep" after missing an open goal against the South Africans, he skewed a golden chance wide inside two minutes before being hooked off by coach Rogerio Micale early in the second-half.
Iraq could even have snatched a shock win when Mohanad Abdulraheem's first-half header came back off the inside of the post.
Renato Augusto had Brazil's best chance when he shot over the gaping goal deep into seven minutes of stoppage time.
Romanian referee Ovidiu Hategan waived away strong claims for a penalty moments later when Gabriel Barbosa tumbled inside the area.
Atletico Madrid's Angel Correa scored and set up Jonathan Calleri's winner as 10-man Argentina got its challenge for a third Olympic gold back on track with a 2-1 win over Algeria in Rio.
Argentina coach Julio Olarticoechea was put in charge for the Games just weeks before his team's opening 2-0 defeat to Portugal. Olarticoechea took over from Gerardo Martino who quit after a second Copa America final defeat to Chile in as many years.
Olarticoechea's options were slashed by a number of high-profile pullouts and European clubs not releasing their players so close to the start of the season.
However, it was Calleri, called in at the last minute to replace Luciano Vietto, who bundled home the winner 20 minutes from time.
Argentina still needs to beat Honduras in its final Group D game on Wednesday to qualify for the quarterfinals.
Portugal is assured of its place in the last eight after beating Honduras 2-1.
Goals from Tobias Figueiredo and Goncalo Paciencia cancelled out Alberth Elis's first minute opener.
World champion Germany also dug itself out of trouble as a stoppage-time equalizer from Arsenal winger Serge Gnabry salvaged a thrilling 3-3 draw against South Korea in Salvador.
Germany lies in third place in Group C, two points behind Mexico and South Korea.
It faces the prospect of having to beat Fiji by at least four goals in its final group game to progress, if South Korea's final match with Mexico also ends in a draw.
Defending champion Mexico needed a second-half fightback to stave off one of the biggest shocks in Olympic football history to beat Fiji 5-1.
Fiji benefited from New Zealand's disqualification for fielding an ineligible player to qualify for the Olympics at last year's Pacific Games. It was thrashed 8-0 by South Korea on its debut on Thursday.
However, it led 1-0 at half-time in Salvador thanks to Roy Krishna's opener.
Erick Gutierrez was Mexico's savior as he struck four times in the second-half.
Sadiq Umar headed 1996 winner Nigeria into the quarters with a 1-0 win over Sweden.
Colombia hold a one point advantage over Japan and Sweden in the fight for second place after its second 2-2 draw against Japan in the Amazonian city of Manaus.