Both Paraguay and Japan made surprising surges through group play to advance ahead of higher-ranked rivals, but only one of them will achieve its first quarterfinal appearance at the World Cup.
The two hopeful nations engage in perhaps the most unlikely round of 16 matchup Tuesday in Pretoria, and each may feel it has a golden opportunity to advance.
Despite being placed alongside Italy in Group F, Paraguay finished atop the group and helped facilitate the defending champion's elimination.
Following a 1-1 draw with the Azzurri in its opening match, Paraguay beat Slovakia 2-0 before outshooting New Zealand 17-4 during a scoreless draw Thursday to secure first place in a World Cup group for the first time.
"We have something to celebrate but we're not getting carried away," goalkeeper Justo Villar said. "We've taken a big step forward but there's still some way to go. The match we really need to win is the next one. There's a lot of excitement in the camp and we've got to fuel that with good results."
Villar's error led to a goal by Italy's Daniele De Rossi, but that was the only one La Albirroja have conceded in the tournament. Japan coach Takeshi Okada is expecting to encounter a similarly staunch defense Tuesday.
"They're a team that knows how to play when it really counts," Okada said. "All South American teams are not necessarily the same, but Paraguay have a very similar game to Chile. They've got a very solid back line, they push forward in numbers and switch quickly from defense to attack."
Japan's attack looked very good against Denmark in a 3-1 win Thursday, a result that pushed the Blue Samurai into the knockout stage for the first time on foreign soil. Japan lost 1-0 to Turkey in the round of 16 as co-host in 2002.
Japan began the tournament lower in the FIFA rankings than any of the three other Group E teams, but it beat Cameroon 1-0 in its opener and challenged the group-winning Netherlands in a 1-0 defeat.
"Since we've come to South Africa things have changed, it's hard to say if it's one specific thing," goalkeeper Yoshikatsu Kawaguchi said. "Once we got our first win, we started to play better."
Keisuke Honda has been Japan's biggest offensive threat, tallying two goals and setting up Shinji Okazaki's late strike against the Danes.
Paraguay still hasn't gotten a goal from a striker, and Manchester City forward Roque Santa Cruz will be looking to step up.
"Our job goes further than scoring goals," Santa Cruz said. "We have the job of making it difficult for the (opposing) defense to generate offense."
La Albirroja lost to England, France and Germany in their three previous attempts to reach the quarterfinals. Paraguay has gone 2-1-3 in six previous meetings with Japan, but none were at the World Cup.
The winner faces either Spain or Portugal in the quarterfinals.
