The 26-year-old smashed 156 runs off 63 balls to help Australia beat England in a Twenty20 match at the Rose Bowl on Thursday, bettering the previous international record of 123 scored by New Zealander Brendon McCullum.
Australia's tally of 248 for six was the second highest score in an international T20 after Sri Lanka's 260 against Kenya in 2007, and set up their first victory since they beat West Indies in a one dayer in early February.
"It was just one of those days when everything hit the middle of the bat and things went my way," Finch said in Southampton.
"It was a beautiful wicket. The outfield was lightning and all you had to do was hit the gap early and you got maximum value.
"It was a beautiful place to bat, I think the bowlers won't be too happy about it though."
In 70 minutes of batting fireworks, Finch hit 11 fours and a T20 record 14 sixes, one off the bowling of Stuart Broad bringing up his first international century from 47 balls.
The opener said he was unaware he had a chance to better South African Richard Levi's 45-ball record for the fastest T20 century.
"I think you saw, I started blocking the hell out of it around 100," he laughed. "I did get a little bit nervous but I had no idea what the record was."
Finch hoped his blistering innings would help him stake a "pretty good" claim to stay in the side for the second T20 against England in Durham and the one-day series to follow.
Although Australia's winless streak in Test cricket is now guaranteed to extend to 11 months, Finch thought breaking the drought in all forms of the game augured well for the limited overs series against England.
"It's huge boost, there's a lot of new players in so there's a lot of fresh guys ready to go," he said.
"So I think there hasn't been a lot of baggage carried over from the Ashes ... I think everyone's really confident going into the series."
The match was also notable for being the international debut of leg spinner Fawad Ahmed, a former refugee from Pakistan who benefited from a change in the law to get his Australian citizenship in July.
"There's a huge excitement around the group about Fawad playing," Finch said of his Victoria state team mate, who failed to take a wicket and cost 43 runs in tricky conditions at the Rose Bowl.
"He bowled the house down in domestic cricket last year and I think given the conditions, he adapted really well.
"It's never easy when batsmen are trying to attack you so much but he's got a wise head on his shoulders and I thought he did really well today."