Google Inc promoted a Groupon-like daily deals offer on its home page on Wednesday for the first time, a rare instance of the Internet giant using its prized online real estate for advertising.

The world's No.1 Web-search engine launched a daily deals business in certain cities this year -- called Google Offers -- to try and counter Groupon's increasing draw for Web surfers.

Wednesday's daily deal was the first time a Google Offers product has been promoted on its minimalist website, and may signal an escalation of competition with Groupon -- which has filed for an IPO sources say could happen as soon as next month.

The pair are vying for advertising dollars from local businesses, such as restaurants and retail stores.

A short blurb beneath Google's sparse home page -- a valued window into a plethora of services from email to maps -- offered visitors $25 tickets to New York's American Museum of Natural History for the discounted price of $5.

We occasionally include a link on the Google home page that points users to important information, whether it be about a relevant cause, a new product or an offer, a Google spokeswoman said in a statement emailed to Reuters.

Users can benefit from learning about great deals from local organizations.

Google has traditionally resisted using its home page for promotions, save for occasionally pushing in-house products such as its Chrome Web browser or its now-defunct Nexus One phone.

Google generated 96 percent of its roughly $29 billion in revenue last year from advertising. Most of it comes from ads that appear alongside Google's search results.

(Reporting by Alexei Oreskovic and Alistair Barr; Editing by Tim Dobbyn)

This story corrects to Nexus One phone, not Nexus S, in the 8th paragraph.