Mexico 2-2 Germany

(Peralta 52', Pizarro 63' - Gnabry 58', Ginter 78')

Germany stumbled to a draw against an otherwise determined Mexico side in Thursday's opening evening of athletic festivities, picking up a point in a 2-2 result at the Arena Fonte Nova.

Despite fielding a squad full of exciting young Bundesliga talents - as well as the senior, proven partnership of Lars and Sven Bender in the centre of midfield - Horst Hrubesch's side spent much of the game chasing their Mexican counterparts across the pitch.

Indeed, it became abundantly clear from the opening exchanges of the match that Germany's defense were struggling with the opposing attack, when Timo Horn was forced in to a fantastic save to avert Hirving Lozano from simply tapping the ball in at the back post unmarked.

An injury to Leon Goretzka 30 minutes into the game stole the attention from a poor opening half for the Germans, as they went in at half time in slight surprise at still being level with Mexico.

Gnabry's time to shine

However, the man to replace the fallen Schalke starlet, Arsenal's Serge Gnabry, was moved out wide and made an instant impact by offering pace and a direct route to goal that had initially been missing.

Although Mexico took the lead with a looping header just seven minutes into the second half, it was the Arsenal youngster who darted into the Mexican box shortly after to slot home the German equalizer.

With Gnabry on one wing, Julian Brandt on the other and Max Meyer through the middle, Germany began to offer some real bite in the Mexican half. Yet the poorly constructed back line still struggled with Mexico's counterattacks.

This once again became abundantly clear when a cross into the German box found Marco Bueno, who smacked a header off the crossbar before Rodolfo Pizarro casually bundled the ball over the line. Despite the best efforts of Germany's attack, they continued to fall behind to their opponents on the night.

Yet Arsenal's wunderkind wasn't finished. Six minutes after Mexico's second goal, Gnabry went on another weaving run and forced a save from the goalkeeper and earned his side a corner. Nine minutes later the winger again decided to go alone with a run and shot that forced Alfredo Talavera to once again concede a corner.

Indeed, it was the corresponding set piece which allowed Brandt to then find Matthias Ginter in the box to fire home a header and perhaps a deserved equalizer for the second time that night. Germany finished the game level on goals and points and had their early substitute to thank for it.

Brazil 0-0 South Africa

Further frustration was found for another famous soccer nation on Thursday, when hosts Brazil huffed and puffed but failed to blow South Africa's house down.

Despite having Barcelona star Neymar to lead the line, Brazil failed to convert any of the 21 attempts made on goal throughout the 90 minutes.

Although South Africa were reduced to 10 men on the hour mark when Mothobi Mvala picked up a second yellow card, Owen Da Gama's side dug deep and held out for a vital draw.

Following the sound of boos from the home fans after their opening game, Brazil will next face Iraq and then Denmark in the final Group A game, as they continue their push to pick up an Olympic gold in soccer for the first time in their history.

Fiji 0-8 South Korea

Bayer Leverkusen's Ryu Seung-woo scored a hat-trick as South Korea scored seven second half goals to destroy Fiji in Salvador. Former Leverkusen forward Son Heung-min added one as Korea aim to go one step further than their third-place finish at the 2012 London Olympic Games.

Nigeria 5-4 Japan

Nigeria brushed aside concerns over their preparation for the Olympic Games, winning a topsy-turvy contest against the heavily-fancied Japanese.

Samson Siasia's side arrived in Brazil five hours before kick-off, with his side stuck in the United States due to the wrong size of aircraft being booked for the team. There was no jet lag as Nigeria scored inside six minutes through Roma youngster Umar Sadiq.

Japan equalized a minute later, but Nigeria hit back within a minute - Oghenekaro Etebo scoring the first of his impressive four goals on the night. Salzburg's Takumi Minamino and Arsenal's Takuma Asano got on the scoresheet, but the Nigerians held on despite tired legs showing towards the end.

Sweden 2-2 Colombia

Sweden and Colombia played out a thrilling 2-2 draw at the Amazonia Arena. Colombia's 31-year-old striker Teofilo Gutierrez, who plays for Sporting Club de Portugal, opened the scoring after 17 minutes.

But Sweden hit back with two goals either side of the break. Dorlan Pabon secured a point for the Colombians, striking home a penalty kick with a quarter of an hour remaining.

Portugal 2-0 Argentina

Portugal, champions of Europe, held off a talented Argentina side to take the points in the first game of Group D. Rui Jorge's side netted both goals after the interval - the first from FC Porto's 22-year-old striker Goncalo Paciencia, and the second from Pite, six minutes from time.

Argentina, which has won two gold and two silver medals at the Olympic Football Tournament, has named highly-rated players such as Angel Correa from Atletico Madrid and Jonathan Calleri of Brazilian side Sao Paulo.