“I had a few hours to prepare, but there’s no excuses from my end,” Millman said.
“That performance is on me. I couldn’t have been better prepared from [captain] Lleyton [Hewitt] and the coaching staff. Yeah, that’s on me.
“There were a few points in it but in the best-of-three set format, that can happen.
“Obviously, it’s a little more disappointing when you have those chances and you don’t take them but this one just hurt a lot.”
Alex de Minaur produced yet another brilliant display to underline his credentials once more as one of the world’s most exciting players, with victory over fellow young gun Denis Shapovalov.
The 20-year-old Australian No.1 came from a set down to win 3-6 6-4 7-5 to level the tie at 1-1 and spark wild celebrations from the Australian bench.
However, it proved to be short lived and John Peers and Jordan Thompson lost the doubles to Shapovalov and Pospisil in straight sets to hand Canada a 2-1 victory.
De Minaur, who has now won 41 matches in 2019, said the win gave him mixed feelings as it was in a losing cause.
“I was going to do everything in my power to try to give myself chances and fight till the end and, you know, that’s what I did,” de Minaur said.
“It ended up going my way and it was good to turn that one around but the team winning is the most important thing.”