Short blasted 41 off 26 balls against England and shared a blistering opening partnership of 86 with Travis Head as Australia won the first Twenty20 by a comfortable 28 runs in Southampton.
Short missed the Scotland series for the birth of his first child, but was glad to slot in and perform against England.
"I only found out last night," Short told reporters of his selection.
"Obviously, with Davey Warner out, you sort of know that the spot's opened up.
"But then Jake Fraser-McGurk has been playing the last few games in Scotland, so you never know where you sit.
"But I'm glad I sort of took that opportunity tonight and played my role to help the team with a win."
Fraser-McGurk was seen as the man most likely to take the opening spot, especially after Warner captioned a picture of himself and the young opener with "All yours now champion", after his retirement in June.
However, Fraser-McGurk sandwiched a 16 between two ducks in Edinburgh in the three-match series against the Scots.
Short missed out on a place in Australia's squad at the T20 World Cup in the US and West Indies, and the Southampton match was his first T20I since February.
He said he was fixed on securing a regular spot in the Australia line-up.
"It's a personal sort of goal of mine. I've been in and out of the side recently over the last 12-18 months," said the Ballarat-born batter.
"Now Dave is out, I'm really trying to take this opportunity and cement my spot in this side."
Warner's retirement also left a big hole in the Test side, which was filled, unconvincingly, by Steve Smith against West Indies over the home summer and on tour to New Zealand.
Head coach Andrew McDonald has said selectors were still weighing up the merits of retaining Smith as an opener for the five-Test series against India in the home summer.
"While we've got an eye to it, we haven't made any firm decisions around that one," he told local radio station SEN.Â
