Gold medal favourites Brazil became the first team to qualify for the quarter-finals as they came from behind to beat Belarus 3-1 at Old Trafford, thanks to an inspired performance from Neymar, who scored and set up the two other goals.
Brazil's victory, thanks to a header from Alexandre Pato, a 30 metre free-kick from Neymar and a brilliantly-taken third by Oscar after being set up by a backheel from Neymar, meant Brazil have six points from their opening two Group C matches and are through to the knock-out rounds.
However they had to come from behind after Brazilian-born Renan Bardini headed Belarus in front after eight minutes.
In the other Group C match played earlier at Old Trafford in Manchester, Egypt wasted plenty of chances in a 1-1 draw with New Zealand which did neither team's chances of advancing much good. Belarus, who are second, will qualify with a win over Egypt on Wednesday.
Chris Wood put the Kiwis ahead after 17 minutes before Mohamed Salah equalised after 40 minutes for his second goal of the tournament. Egypt wasted chances in the second half and now must beat Belarus themselves to have any chance of going through.
New Zealand's Ryan Nelsen summed up the game by saying: "At the end it was a case of you score, we score. Both teams needed a win and it showed in the end. Both teams will be disappointed by the result."
In other early action, Mexico beat Gabon 2-0 in Coventry with two goals from substitute Giovani Dos Santos, who lives in the Olympic city of London and plays for Tottenham Hotspur.
Mexico have four points in Group B and look set to advance to the last eight, while their group opponents South Korea and Switzerland were playing later.
Sunday's late matches included hosts Britain playing the United Arab Emirates in front of an expected 80,000 crowd at Wembley.