Qantas Airways' alternatives to a partnership with Emirates were either to collaborate with an Asian airline or totally cut all European services.
Working with Emirates, however, was the best option because of the Dubai-based carrier's "complementary network", said the Australian flag carrier's chief executive Alan Joyce.
Speaking at the Oneworld carrier's annual general meeting, Joyce revealed that Qantas held talks with Singapore Airlines, Cathay Pacific Airways and Malaysia Airlines before it was approached by Emirates.
"We were very pleased when Emirates came to us to say that we can work together and be complementary," said Joyce. "The other option is the complete demise of Qantas's operations to Europe so it's important that we work together."
He stressed that Qantas is not "handing over the flying" to Emirates, but leveraging on the Gulf carrier's strong hub and network to return to continental Europe.
The collaboration is also expected to improve business and thus, secure jobs of Qantas's employees, he added.
"We're working together because we have a complementary route network. We believe we need a viable solution to our European network," said Joyce.
Middle Eastern carriers have significant advantages over Qantas because of their strong hubs, government-paid infrastructure and a low-tax regime, he added.
In his opening address, Joyce noted that the proposed extensive alliance with Emirates is the most significant in Qantas's history and will "revitalise" Qantas International on the competitive kangaroo route.
Qantas also decided to terminate its 17-year relationship with IAG unit British Airways. The two carriers co-operate on services between Australia and the UK, but Joyce said that BA was also struggling on the route and that the agreements they had "were no longer delivering".
He did not touch on competitor Virgin Australia's recent moves to take over regional carrier SkyWest and its bid to take a controlling stake in low-cost carrier Tiger Airways Australia. These put Virgin squarely up against Qantas's lucrative fly-in fly-out business and its low-cost unit Jetstar.
Qantas's focus remains on returning its international business to profitability and to secure approval for the Emirates partnership.
Under the 6 September agreement, Qantas and Emirates plan to start on an extensive partnership to collaborate on routes and frequent flyer benefits, shifting the Australian carrier's hub for European flights to Dubai from Singapore.
The partnership, which is being scrutinised by Australian regulators, is scheduled to commence in April 2013 and run for at least 10 years.