Highlights - Argentina 1-0 Nigeria
Argentina midfielder Juan Sebastian Veron has been ruled out of Thursday's World Cup Group B game against South Korea because of a leg injury.
The former Manchester United player is being rested as a precaution after suffering a calf muscle strain.
Argentina coach Diego Maradona said he did not want to risk Veron aggravating the problem and ending his World Cup.
Maxi Rodriguez is set to deputise, in what is likely to be the only change from the side that beat Nigeria 1-0.
Maradona admitted it was a difficult decision to leave out Veron but said the 35-year-old playmaker could return for the final group game with Greece.
The coach told a press conference: "It was a difficult decision to leave Seba out, because he really wants to play and of course nobody wants to miss out on the World Cup, but we have to deal with the problem of risk.
"We don't want the injury to get worse, we don't want Veron's World Cup to end. I need him.
"He understood perfectly well that it was the best for the team. We'll just let Veron rest and recover and we hope he can play against Greece.
"Although we may be losing a very important player I think Maxi Rodriguez is going to do a wonderful job."
South Korea top the group on goal difference after the first round of matches, following their 2-0 victory over Greece.
The tournament has yielded fewer goals than expected so far with Germany's 4-0 thrashing of Australia and Brazil's 2-1 win over North Korea the only games to feature three or more goals.
But Maradona is confident the level of excitement will improve.
"I'm having a wonderful time to tell the truth, to me a World Cup is something that's quite amazing," said Maradona.
"I'm not worried by the fact there aren't many goals, I'm sure there will be goals, I'm sure the players will see to that.
"Of course in the first matches you are more careful, perhaps more careful than you should be."
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