Internet search, as a long-time key driving force for online ads, could possibly face its "first negative sequential growth" in the first quarter of 2009, according to a Citigroup analyst, Market Watch reported.

That, in turn, "will be a likely drag on Google Inc.'s revenue," Citigroup analyst Mark Mahaney stated in a note to clients Monday.

Search advertising market giant Google could keep a two percent sequential gain in net revenue in the first quarter, said Mahaney, although that "assumption may now be at risk," MarketWatch reported.

The online giant is likely "acutely aware of global economic trends," due to the data retrieved from its search service, said Mahaney.

He noted that searches for the keyword "Downturn" have quintupled recently, MarketWatch reported.

In addition, Google has reduced its cost "significantly," including layoffs of temporary employees, to get through tough times ahead.

According to Mahaney, in the long term, Google is likely to "come out of the current recession with an even firmer lead in the online search market," while rival Microsoft seems "unlikely to seriously challenge Google in search," MarketWatch reported.