Kyrgios strangely sidelined as Aussies crash out
Australia are out of the Davis Cup after John Peers and Jordan Thompson lost the quarter-final doubles rubber to Canadian duo Denis Shapovalov and Vasik Pospisil.
Peers and Thompson went down 6-4 6-4 as Canada booked a semi-final against Russia or Serbia.
Earlier, Alex de Minaur levelled the tie at 1-1 after beating Shapovalov following Pospisil's win over John Millman - a late replacement for Nick Kyrgios.
Mystery surrounded the late scratching of the in-form Kyrgios, with Tennis Australia officials merely saying the 24-year-old had not been nominated.
The 30th-ranked Kyrgios had won both of his matches in the group stage without dropping a set.
Millman lost to Pospisil 7-6 (6) 6-4, but de Minaur evened the series with a 3-6 6-3 7-5 win over Shapovalov in a battle of 20-year-olds.
Shapovalov and De Minaur had previously met in the 2015 junior Davis Cup final and in the 2016 Wimbledon boys final.
Canada had not beaten Australia in nine previous Davis Cup meetings, with only one match victory.