The Stoke forward scored in the Super Eagles’ 1-0 win over Bosnia and Herzegovina on Saturday – a win that gives them a real opportunity of progressing through to the last 16.
After netting a vital winner, Odemwingie says he is hopeful of making Stephen Keshi’s starting XI in Porto Alegre on Wednesday.
He told FIFA’s official website: “I earned myself a starting position and it was important to work hard to keep it, especially before a big game like Argentina, which is a dream for every player to play in.
"I'm so happy for the country, our fans, the team. It was maybe one of the hardest three points in my career, though."
The African side will qualify for the knockout stages if the Bosnians avoid defeat to Carlos Queiroz’s Iran, regardless of Nigeria’s result against Argentina.
After scoring past Bosnian goalkeeper Asmir Begovic, Odemwingie admitted he wasn’t particularly confident of beating his Stoke team-mate from five yards out.
“Saving shots from close distance is one of the stronger sides of his game,” the Nigerian forward said of Begovic.
"He is a great guy. He knows I have a good shot and I tried to shoot a few times. I'm sure he is going to tell me off when I get back to Stoke.
"I had to do it for my country but I was so happy to see him on this stage and I exchanged shirts with him at the end of the game."