Will Costa Rica be the team that fans throw their support behind if their first choice is knocked out in the Group stage?
From the Joel Campbell baby celebration to the shocking upsets of Uruguay and Italy, Costa Rica is quickly growing its fan base.
"Los Ticos" is stealing the headlines from Group D powerhouses Italy, Uruguay and England.
On the streets of San Jose, thousands of people poured out to celebrate. Government offices, stores and schools came to a halt as everybody celebrated the historic win.
So just how big is this upset? Where does it rank among other significant World Cup surprises?
The answer is — not as high as you might think.
There are at least five others from recent World Cup history (the past 24 years) — including three from 2002 — that are probably bigger than Costa Rica's takedowns of Italy and Uruguay.
In chronological order:
1990 — Cameroon 1, Argentina 0
Cameroon kick-started African footballing with its dramatic performance at the 1990 World Cup, making a run all the way to the quarter-finals. The Indomitable Lions began the tournament with a win over Diego Maradona and Argentina, knocking off the defending champs.
1994 — USA 2, Colombia 1
This match will be remembered for the tragedy that happened afterwards, rather than the result on the pitch. But don't forget, Colombia was one of the pre-tournament favourites at USA '94. The Americans buoyed by their home fans found something extra and knocked off Colombia in their Group stage match. Colombian captain Andres Escobar's own goal was the winner. He was murdered upon his return home.
1994 — Bulgaria 2, Germany 1
Along with Colombia, the Germans were also seen as a safe bet to go deep into the 1994 World Cup. Then they came up against a relentless Bulgarian team in the quarter-finals. Bulgaria came from behind to win.
1998 — Croatia 3, Germany 0
This was a coming out party for striker Davor Suker. He won the golden boot and helped Croatia to a surprise third-place finish. Beating the heavily favoured Germans in the quarter-finals was the most shocking defeat of that run.
2002 — South Korea 2, Italy 1
As co-hosts of the 2002 World Cup, South Korea had a magical run to the semifinals, defeating Italy, and then Spain. South Korea's win over Italy came in extra time, aided by some questionable officiating and the short-lived Golden Goal rule.
2002 — Senegal 1, France 0
Upstart Senegal took down the defending World Cup champions in 2002, beginning a run that would go all the way to the quarter-finals.
2002 — Turkey's 3rd place finish
Senegal ran into a red-hot Turkey squad, fresh from not having been at the World Cup in 48 years. Turkey may have been the beneficiary of other upsets along the way — it faced Japan and Senegal in the first two knockout stage matches, winning both. Turkey hasn't qualified for a World Cup since then, either.