Double Lions tourist Jonny Wilkinson started the narrow victory over the Pumas but his off day with the boot and England's failure to create many try-scoring opportunities means the shirt is still very much up for grabs ahead of the remaining pool clashes with the Georgians, Romanians and Scots prior to a potential quarter-final against France or New Zealand.
And while Flood admits he was gutted not to start the first group game in Dunedin, he insists he is now fully focused on taking the next chance that comes his way.
"It was really frustrating not to be part of the first win but you get over it pretty quickly and realise it's a massive squad effort," said Flood.
"It is difficult but you take it on the chin. In coming weeks the squad is going to be important.
"You can't let it knock you. All I can do is go out there and try to prove them wrong on the decision they're making. You hope you get the chance and make an impact, and then put your hand up when you get an opportunity.
"They haven't said 'You're second fiddle or whatever'. Each week is selected on form more than anything else."
Flood's battle with Wilkinson for the outside-half role has been a long-drawn out saga for both club and country. The pair were together at Newcastle before Wilkinson headed for Toulon and Flood left for Leicester.
But while everyone else seems to be searching for some sort of bitter rivalry between the two, Flood insists he simply looks up to and tries to learn from England's World Cup winning hero.
"You get asked it every other day. Even my mum asks me the same questions," added Flood.
"We get on better than most people think. I never saw it as a competition but as a chance to learn from an outstanding player. When you're 18 or so and you see who's on top of the world, it's amazing to be there.
"It's a talking point outside the squad but between me and Jonny there's no big high five or handshake of congratulations about getting the start. It's just down to business."