The Manchester City forward is considering international retirement despite being just 26 and warned he was unlikely to play for Argentina at the next World Cup.
Tevez admitted last month that he had fallen out of love with football after Argentina's disappointment at South Africa 2010 and he predicted staying at City for just two or three more years - despite having four years left on his Eastlands contract.
Ups and downs: Carlos Tevez celebrates a goal against Spain but looks 'tired and old' after his horror miss against Sunderland
After scoring in his country's 4-1 victory against Spain on Tuesday, he was far from upbeat, saying: 'I'm tired. I'm 26 - I'm old.
'I'm still into it - to play, to be there. But I don't know if I will make it until 2014. I don't know. In reality, I think it will be tough.
'To be on the national team you have to be 100 per cent and play with all you have. I'm not blaming anyone. It's my issue. It's a physical question. You can't play on the national team at 60 per cent.'
The anguish is at odds with the all-action enthusiasm that Tevez gives when playing, but he is struggling to cope with living apart from his daughters.
Roberto Mancini has made Tevez his captain at City and the striker was in fine form to score two in a 3-0 win against Liverpool.
However, the former West Ham player has not hit the net in four other club appearances and suffered what will surely be remembered as one of the misses of the season last time out against Sunderland, which City lost 1-0.
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