Brisbane - Mercurial Australian Nick Kyrgios on Sunday pulled out of his ATP Cup rubber against Canada's Felix Auger-Aliassime in Brisbane with back soreness.
He was replaced by Australian No 3 John Millman who went on to thrash Auger-Aliassime 6-4, 6-2 in front of his home crowd on Pat Rafter Arena.
Kyrgios was in superb form in the opening tie against Germany, putting on a serving masterclass as he downed Jan-Lennard Struff in straight sets.
In the second singles rubber, Australia's Alex de Minaur upset Canadian No 1 Denis Shapovalov, 6-7 (8-6), 6-4, 6-2 to give the host nation an unassailable 2-0 lead.