But after watching the Sydney FC goalkeeper's performance against his English Premier League side, he's got one thing clear.
"If he was with us, we made a mistake," Wenger said.
"At the end of the day I would say their goalkeeper was man of the match."
Redmayne took his game to a new level in Sydney's 2-0 loss to the Gunners on Thursday night.
The 28-year-old made a string of stellar saves, even repelling Danny Welbeck from the penalty spot, in a sign he's very much pressing for the first-choice spot Danny Vukovic left vacant.
Perhaps fittingly, Redmayne delivered the finest display of his career against the very team he'd come so close to joining.
Then 16, he trialled at Highbury for a fortnight and nearly had pen to paper when the club decided to sign a 15-year-old Wojciech Szczesny instead.
Redmayne, who remains a Gunners fan despite the let-down, could hardly believe what he was hearing when told Wenger had singled him out for praise.
"I guess it's pretty exciting," Redmayne said.
"But it's always good to play well in the first game of the year, and I'm sure I can build on that and get on a roll."
Redmayne's A-League career has been something of a rollercoaster, hardly playing for Central Coast Mariners and Brisbane Roar before cementing and then losing his No.1 place at both Melbourne City and, in the first half of last season, Western Sydney Wanderers.
He puts his current form down to a reunion with his first goalkeeping coach, John Crawley, and a welcoming Sky Blues set-up that makes him feel more comfortable than at any previous clubs.
Coach Graham Arnold is already on the hunt for a gloveman to replace Belgium-bound Vukovic, but made a point of silencing Redmayne's critics.
"I've always had a lot of faith in Andrew Redmayne," Arnold said.
"I think he's copped a bit of harsh criticism over the last couple of years but two years ago he helped the Wanderers to a grand final as No.1 keeper."