Hosts Spain and Australia made smooth progress to join Canada in the last eight of the Davis Cup Finals but elsewhere in La Caja Magica it proved a more trying day for players, organisers and fans.

World number one Rafael Nadal sealed top spot in Group B for Spain as he crushed Croatia’s Borna Gojo 6-4 6-3 to give his side an unassailable 2-0 lead after Roberto Bautista Agut had beaten Nikola Mektic 6-1 6-3.

It ended a woeful few days for reigning champions Croatia, who sacked captain Zeljko Krajan days before the finals and were without injured talisman Marin Cilic. They left with two losses.

Australia set up a quarter-final against Canada on Thursday with victory over Belgium but retired from the dead doubles rubber after playing one game in another blow for the revamped tournament’s credibility.

With the rubber having commenced after midnight, Australia captain Lleyton Hewitt said it was an “easy decision” to retire and that doubles player John Peers needed to rest a sore elbow.