Just in case the 23-year-old leg-spinner was in any doubt, though, former grade cricket team-mate Brad Haddin is happy to confirm - as a potentially steely opponent at the SCG - that Australia's batsmen will be determined to put the new boy under maximum pressure.
Borthwick and Haddin played on the same side earlier this winter, for Northern Districts in Sydney's grade competition.
But Australia's wicketkeeper-batsman will be making no allowances for any camaraderie built up between them back then.
At a suggestion the hosts will 'get after' Borthwick, Haddin - often more succinct in a press conference than he is perhaps out in the middle - said: "No doubt."
He had prefaced those two words with an inscrutable: "It'd be interesting to see how we approach him...
"It'd be an exciting time for him, first Test in an Ashes campaign."
Borthwick, whose winter in Australia was supposed to come to an end last week before flying home and then on to Sri Lanka with the England Lions, had a last-minute re-instruction to instead join the Test squad following Graeme Swann's mid-series retirement.
So it is that, with England 4-0 down and in imminent danger therefore of a second whitewash in their last three tours here, he is one of several who may be drafted into a losing team to try to somehow stop Australia.
He is well aware the home batsmen will be giving him no peace - but as a leg-spinner, that is an occupational hazard.
"I see that as a challenge," he said.
"If batters do want to come at me, it gives me a chance to get wickets.
"If they do, I'll accept that challenge...try to spin the ball...and give it my best shot."
Borthwick believes he has benefited significantly from his short stint in grade cricket.
"I was playing for Northern Districts in Sydney," he said.
"It was perfect for me.
"The standard is very good, very competitive. You come across some good players, especially when the state players are involved."
Team-mate Haddin, it seems, made a favourable impression.
"In my second game, Brad played," Borthwick said.
"He seems okay, seems a good fella."
He may be about to discover if Haddin is quite so pleasant in opposition.
Whether they meet at close quarters in the middle or not this week, though, Borthwick is relishing his unexpected opportunity to be in an Ashes squad.
To date, he has just three limited-overs caps to his name.
"It's just a great feeling for me to be a part of an Ashes tour," he said.
"I'm thrilled to be here, and really excited.
"It'd be a great opportunity for me (to play), and a great challenge.
"I'll take it with both hands and I'll try my best."