Flintoff, who played 79 Tests in an 11-year career, taking 226 wickets and scoring 3,845 runs, was also a key member of the triumphant 2005 team and he said: "I loved playing Test cricket - it feels strange talking about it in the past tense.
"It's one of those things you don't want to end - but like all things it comes to an end at some point and I couldn't ask for a better way for it to finish.
"To win the Ashes twice is everything. I'm proud to be English and represent my country and I feel very fortunate to do it on and off for the last 10, 11 years or so."
When asked if he had achieved greatness, Flintoff added: "The obvious answer is no. That's the Bothams, the Sobers, the Imran Khans, the Tendulkars, the Ricky Pontings, who achieved greatness over a long period of time, playing Test after Test after Test.
"I have performed at times and I am proud to have done that.
"For the bulk of my career I have played through pain and with injury, so to be out on the field was an achievement in some ways - but as for greatness? No."
Flintoff's Test career was undermined by a series of injuries and he visibly struggled through the recently completed Ashes series. He was left out of the fourth Test at Headingley and bowled at well below full pace at The Oval.
He categorically ruled out any possibility of a return to the Test arena in the future.
"I have made my decision, or rather the decision has been made for me," added Flintoff.
"I have had all these operations - bowling and Test cricket do not seem to match. Now I am setting my sights on being the best one-day player in the world."
If there's any lesson to learn from 2005 now, it's to go for domination, to try to get number one in the world
Flintoff was the Man of the Series in 2005 as England defeated Australia 2-1, a result that sparked huge celebrations.
Television shots the day after the victory was clinched showed the all-rounder looking visibly worse for wear, but he was keen to stress his enjoyment had been more low key in 2009.
"I remember 2005 - contrary to popular belief - 2005 was fantastic, it almost snuck up on us," said Flintoff.
"I lived for the moment then and celebrated hard. But this time it was something which I savoured.
"It was quite nice - all the families came over. I sat with my wife and my kids, my dad who has done so much for me throughout my career.
"I was able to have a beer with my dad. It was very different but in a lot of ways far more enjoyable."
Stuart Broad won the Man of the Match award in the decisive final Test following a destructive spell of 5-37 as Australia were bowled out for 160 in their first innings.
The Nottinghamshire player also scored 37 and 29 batting at number eight - prompting suggestions that he could fill Flintoff's role as England's all-rounder.
"He's better than me in a lot of ways," said Flintoff of Broad.
"He's only 23 and he's performing at the highest level. Broady has a lot of potential but he's already showing it. Changing the course of the game at such a young age is very special.
"We have also seen signs of what he can do with the bat. He's not the finished article but he has huge potential. He could bat at number three in the future."
Broad said he would like to bat higher up the order in the future but admitted there was plenty of work to do on his batting before then.
"I think I am a number eight at the moment and I am thoroughly enjoying that," he said.
"But I would love to make it up the order at some stage.
Despite the plaudits being aimed his way the level-headed Broad was quick to play down comparisons with Flintoff and England legend Ian Botham.
"It's a bit surreal being mentioned in the same sentence as those two," he said.
"But I'm not under more pressure now, I will just focus on my own game.
Broad happy with England role
"I'm not in the all-rounder stakes like Botham and Freddie, where they can score big runs, but I would like to be in the future."
Flintoff's close friend Steve Harmison took 3-54 in the second innings on Sunday as England won by 197 runs - and afterwards the Durham bowler said he would "gladly" tour South Africa this winter if picked.
"Anybody who plays for their country never wants to give it up," said the 30-year-old Harmison, who has taken 226 Test wickets.
"If they want to take the side with me in it, obviously I'll not turn them down.
"If they [the England selectors] are saying 'we're going to take this in another direction', then I'll gladly step aside."
Harmison appeared to contradict himself when he said "I don't know in my own mind what I am going to do", but Flintoff is confident Harmison can go on to become one of his country's all-time leading wicket takers.
"If I was Steve Harmison and could bowl like that I would keep going," he added.
"If you ask any batsman in the world 'who do you not want to face' it would be Steve Harmison.
"He could end up being one of the greats for England. He could go on to be our leading wicket-taker of all time. If he wants to, there is still a lot more to come."
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