MOUNTAIN VIEW, California: The collapse of acquisition talks between Microsoft and Yahoo has left the door open to a potential alliance between the struggling internet pioneer and its higher-achieving rival, Google.

The pairing recently completed a short but successful trial that saw a small number of Google-supplied text-based ads alongside the search results on Yahoo's website.

The online search leader offered help, it says, to keep Yahoo's "options" open in the face of Microsoft's unsolicited offer.

The software giant claims the internet duo's temporary alliance contributed in no small measure to the scuppering of its deal with Yahoo.

A not unwelcome outcome for Google co-founder Sergey Brin, who declared at the company's annual meeting: "We really believe in companies having choices about their destinies. It's not about scuttling [the deal].

"They were under a hostile attack and we wanted to make sure they had as many options as possible."

Brin and Google ceo Eric Schmidt remain tight-lipped about the precise details of their current talks with Yahoo, but describe the relationship as "very, very friendly".

Any long-term union between the two, however, would be fiercely opposed by Microsoft and would attract antitrust attention from US regulators, who have already asked questions about the two-week test.

Data sourced from; additional content by WARC staff