Spain must win to guarantee qualification. A draw might be enough if Switzerland cannot beat Honduras. Chile will qualify with a win or a draw. A defeat however could see them go out on goal difference.
It is so tight Switzerland could win and still not progress, or conceivably could lose and still go through. A two-goal victory will guarantee qualification. Honduras have a slim chance, if they beat Switzerland convincingly and Chile do the same to Spain.
Going out at the group stage would be a disaster for Spain, the reigning European Champions. However if they don't beat Chile, one of the few countries with a 100 per cent record in the tournament, tonight in Pretoria the Spanish could well be on their way home, having reclaimed their crown as the world's greatest underachievers.
Victory for Spain on the other hand will guarantee qualifying for the second round and there were signs in their 2-0 victory over Honduras that they are over the effects of the 1-0 defeat to Switzerland. With both Switzerland and Honduras also still in with a chance of qualifying, the time has come for Spain to stamp their authority on the tournament. If they top the group they will probably avoid meeting Brazil in the next round.
"For us it's clear what we have to do – we have to beat Chile," said the Barcelona midfielder Andres Iniesta, who should return after missing the Honduras game with injury. "We've got a clear idea about what we need to do and we're confident of reaching the next round. Nothing else is important."
Spain have looked a pale imitation of the side that conquered Europe two years ago. Their former coach Luis Aragones has been critical of his successor Vicente Del Bosque's decision to field two holding midfielders in Xabi Alonso and Sergio Busquets behind playmaker Xavi, claiming the tactics are too negative for a side with so much attacking ability.
The return to fitness of Iniesta provides Del Bosque with the opportunity to go with a more attacking selection, with Cesc Fabregas and David Silva also available to him. "The idea is to play to our own strengths, take the initiative and take control of the game but we don't know if they will let us," Del Bosque said.
The incentive of avoiding Brazil should be enough to encourage Chile to maintain their attacking style, which should make this tie one of the most enthralling spectacles of the group stages. "It's going to be a totally different game, they are going to come out attacking and we're going to apply our own way of playing," Chile winger Mark Gonzalez said. "All of our attention is on reaching the next round and finishing first in the group."
The group is so tight it could go down to goal difference, and Switzerland can book their place, irrespective of results elsewhere, if they beat Honduras by at least two goals.
"We have our destiny in our own hands, and this is an advantage," Switzerland's German coach, Ottmar Hitzfeld, said. "Honduras' playing style is similar to Chile's, but they don't have the same quality individual players."