Third

aloof

Ruiz was quiet, a bit aloof (a bit cold and humourless perhaps but some would argue that a good ref should have those characteristics), and very concentrated on the match. He does not seem to want to attract the attention to himself.
After Nigerian player Kaita was sent off for kicking a player who had the ball in his hands, the Greeks substituted a defender for a forward and the Nigerians started stalling. As was to be expected and Ruiz wanted none of that. The Colombian let a Greek attack move on while a player was lying on the ground pretending to be injured. Later while following the counter attack by the Nigerians, Ruiz noticed a Nigerian falling a little behind him, a minute later (after a shot on an empty goal went wide) Ruiz booked a Greek for it. Ruiz' vast experience is clearly visible from from his actions. This was finally a really well refereed match by Oscar Ruiz.

match

Again the Greeks just didn't seem to want to win. They didn't go all out even when their opponent had a player less, in fact their top scorer Gekas was substituted. The Greek team kept 5, sometimes 6 players behind in the defense to stop one Nigerian forward. (And the same can be said about the Nigerians: having only one forward with no one behind him).

first

The first ever Greek goal in a World Cup match was made by a Nigerian called Aruna.

Fixed?

About two weeks later allegations started to appear about this match having been fixed. Some Nigerian players had come forward saying some other players had been payed to lose the match. Even FIFA has started investigating.
Match fixing is not about fixers picking the winner against the odds. It is more about betting on a sure winner but specifying the number of goals or the goal difference. In this match the Nigerians went ahead one goal in the first half, then lost 1-2 in the second.
The Nigerian team, by the way, was immediately suspended by Nigerian president Goodluck Jonathan. Again later he took that back, maybe because FIFA told him to or maybe because of all the reactions he got on his Facebook page (this is not a joke, the guy has a facebook page and seems to be very active there)