Google Inc. had slapped a lawsuit against a small Intent company in Ohio in October, seeking $335,000 in unpaid advertising bills. The complaint was a small, regular one, hardly two sentence long.

Google had never expected a response in the first place. But last month, the small website sent back a major 24-page long antitrust lawsuit against Google, accusing the search engine giant of a litany of monopolistic abuses.

As surprised as Google was, what really caught the company's eye was the site's legal counsel, who was none other than Charles "Rick" Rule, the chief outside counsel on competition issues for Google's arch-rival Microsoft Corp. for very long.

"My reaction was, 'What the heck is this?'. It's not every day that a big D. C. law firm like Cadwalader gets involved in a collections lawsuit in Ohio", said Mark Sheriff, an Ohio attorney who represents Google. Mr. Rule is also the representative of another small Internet company that brought an antitrust suit against Google.

The long-standing Google and Microsoft antitrust battle seems to be taking a bigger and more fierce turn. Google says that Microsoft is probably "embarking on a proxy war" against it, through many unrelated cases.