The World Cup in Brazil closes in on its final 16 squads Wednesday as the teams in Groups E and F fight for spots in the so-called knockout round.
The key game in Group F features group-leading Argentina taking on second place Nigeria in Porto Alegre.
A draw would mean both teams move on, but if Argentina wins, that would open the door for Iran to overtake Nigeria with a win over Bosnia and Herzegovina.
In Group E, France is in first place with six points but is not yet assured of a spot in the next round as it faces Ecuador in Rio de Janeiro.
A big win by Ecuador and another blowout victory by Switzerland over winless Honduras would send France home.
Pool play closes Thursday with Group G and Group H playing their final matches.
Greece earned its first-ever spot in the second round on Tuesday, as Giorgios Samaras converted a penalty kick one minute into stoppage time to give Greece a 2-1 win over Ivory Coast.
Colombia, which on Tuesday eliminated Japan, 4-1 in Cuiaba, finished first in Group C with nine points, followed by Greece with four, Ivory Coast with three and Japan with one. Until Tuesday, Greece had not scored in this year's World Cup.
Uruguay also advanced to the round of 16 Tuesday by eliminating four-time champion Italy, 1-0, in Natal.
FIFA opened disciplinary proceedings against Uruguay's Luis Suarez after he apparently bit an Italian player during that match.
FIFA has given Suarez and the country's football association until Wednesday afternoon to give their position on the incident and any relevant evidence.
In the 80th minute of Tuesday's game, Suarez was jostling in front of the goal with Italian defender Giorgio Chiellini when video and photos show what appeared to be Suarez biting into Chiellini's left shoulder.
The Italian immediately dropped to the ground holding his shoulder, then got up and pulled back his jersey to show a red mark to the referee.
There was no foul called against Suarez, who has been banned twice before for biting opposing players. After the game he said, "these are things that happen on the pitch."
Chiellini gave a harsher reaction, saying it was "ridiculous" Suarez was not ejected from the game.
Suarez was suspended for seven matches in 2010 for biting a player while playing in the Netherlands, and earned a 10-match ban in 2013 for a biting incident in England.
He was also suspended once for racially abusing another player.
In Tuesday's other Group D match, Costa Rica and England played to a scoreless draw in Belo Horizonte. Costa Rica had already clinched first place in the group after upsetting Uruguay and Italy.
Costa Rica finished with seven points in Group D, followed by Uruguay with six, Italy with three and England with one.
Brazil, Mexico, Chile and the Netherlands all qualified for the second round on Monday.