Ahead of the tournament getting underway in the United States, many doubted just how seriously the Copa America Centenario was being taken by some of the participants, particularly those from South America. Yet two coaches have already discovered the competition was significant enough for failure to account for their jobs. Both Paraguay coach Ramón Díaz and Brazil coach Dunga were fired after bowing out at the group stage.

Dunga paid the price not just for failing to move the team forward since the humiliation of the 2014 World Cup, but for not having his star man, Neymar, at his disposal for the 100-year anniversary edition of South America’s championship. And Brazil wasn’t the only team to exit in the absence of its talisman. Uruguay, too, made a swift departure without Luis Suárez kicking a ball. With eight teams now remaining, the stakes remain high heading into the knockout phase. Here’s what to look out for in the quarterfinals.

USA vs. Ecuador (Thursday, 9.30 p.m. EDT -- Century Link Field, Seattle)

After an opening loss to Colombia that piled the pressure on the host team, and in particular coach Jurgen Klinsmann, the U.S. responded well, helped by the coming of age of defender John Brooks, to record two wins and finish atop Group A. The success has been built upon trusting an experienced core of players and naming the same starting lineup for three games in a row for the first time in Klinsmann’s three-year reign. That will have to change in the quarterfinals, though, with DeAndre Yedlin ruled out through suspension.

Yedlin’s absence, and the likely inclusion of Michael Orozco, could be a particular problem given the pace and quality Ecuador has on the wings through Swansea City’s Jefferson Montero and Manchester United’s Antonio Valencia. After draws against Brazil and Peru, Ecuador made easy work of Haiti, 4-0. The battle in the quarterfinal could be won in midfield, where Ecuador can count upon the all-round excellence of Christian Noboa, while the U.S. still seeks balance with Michael Bradley and Jermaine Jones.

Predicted score: Ecuador 2-1 USA

Peru vs. Colombia (Friday, 8 p.m. EDT -- MetLife Stadium, East Rutherford, New Jersey)

With James Rodríguez reveling in his role running the show after a dispiriting season at Real Madrid, Colombia looked one of the teams to beat in this competition in wins over  the U.S. and Paraguay. A 3-2 defeat to Costa Rica halted that momentum and cost Los Cafeteros top spot in the group. Yet with James, Carlos Bacca and winger Juan Cuadrado to come back into the side, Colombia must still start as a strong favorite to make it to the last four. Peru, though, will not fear being in the position of underdog. A 1-0 victory over Brazil to secure progress at the five-time World Cup winner’s expense was one of the results of the tournament. And, after reaching the semifinals of the last two Copa Americas, this rarified air is hardly new to Ricardo Gareca’s team. Capable of keeping things tight defensively and with quality in the final third, Peru should not be written off. Still, Colombia’s match-winners could prove decisive.

Predicted score: Colombia 2-1 Peru

Argentina vs. Venezuela (Saturday, 7 p.m. EDT -- Gillette Stadium, Foxborough, Massachusetts)

From the moment its Copa America Centenario campaign kicked off, Argentina has looked like a team on a mission to end a trophy drought that stretches back to 1993. Despite Lionel Messi not yet making an appearance in the starting lineup, the Albiceleste has had far too much for defending champions Chile, as well as Panama and Bolivia. And while Messi has looked jaded at the climax of both the World Cup and Copa America in the last two years, this time he should be nice and fresh. He has already showed that he has lost little of his rhythm from an injury layoff by scoring a hat-trick off the bench against Panama. The loss of Ángel di María to injury could have an impact later in the tournament, but it is hard to think it will prove costly against Venezuela.

After a terrible start to World Cup qualifying, recently installed coach Rafael Dudamel has had made a positive impact at this tournament. His side showed an ability to frustrate the opposition and pounce on the break or from set-pieces in 1-0 wins over both Jamaica and Uruguay and a 1-1 draw with Mexico. Yet Venezuela will surely be overmatched against an in-form Argentina.

Predicted score: Argentina 2-0 Venezuela

Mexico vs. Chile (Saturday, 10 p.m. EDT -- Levi’s Stadium, Santa Clara, California)

The last of the quarterfinals and on paper the pick of the bunch. In Mexico and Chile are two teams that can be scintillating going forward but which have also shown some vulnerability going the other way. It is also a battle of two coaches still in the early stages of their reign who can earn themselves a lot of good will by going deep in this Copa America. Juan Carlos Osorio’s start in Mexico could hardly have been much better, with his win streak stretching to nine games thanks to wins over Uruguay and Jamaica in the group stage before it came to a halt against Venezuela. But that draw came with a number of changes to the starting lineup. And, while constant tactical and personnel adjustments have been a feature of Osorio’s short tenure, an impressive core including Javier “Chicharito” Hernández, Héctor Herrera, Andres Guardado and veteran Rafa Márquez should be back in full force for the quarterfinals.

More doubts hang over Chile coach Juan Antonio Pizzi, having lost four of seven games since replacing the man who led the team to Copa America glory a year ago, Jorge Sampaoli. Even when beating Bolivia in its second match of the group phase, it took a controversial penalty deep into injury time. While the attack looked far better in dismissing Panama 4-2 to reach the last eight, without the ball Chile still lacked the sharpness of its peak. Chile may have the two outstanding individual players on show, in Arturo Vidal and Alexis Sánchez, but Mexico appears the better functioning team.

Predicted score: Mexico 2-1 Chile

Tournament Bracket: The winner between the U.S. and Ecuador will take on the winner of Argentina versus Venezuela in the first of the semifinals next Tuesday, with the winner of Mexico against Chile facing off with the team that comes out on top between Peru and Colombia on Wednesday.