"The way that we're thinking about it is, if you look at the top line, Facebook has two to three times the growth that Google does at this point, and we see a lot more levers for gains, as opposed to Google where it seems to be a cost-containment story at this point," Kessler said in a CNBC "Squawk on the Street" interview.
Kessler made his remarks four days after Google reported quarterly results that beat analysts' expectations and three days after S&P Capital IQ downgraded Google's stock to "hold" from "strong buy."
On Friday, the company's stock set a record for a single-day market capitalization gain.
Nevertheless, Kessler said that the recent upward move in Google shares is distracting investors from some of the company's more apparent risks. "That's something that people need to be mindful of, especially after the gains this year," he said.
"There's still a lot of competition. I think growth is going to be interesting as we look out a couple of years from now and then think about what's going on from a legal and regulatory perspective. At roughly 25, our estimate for this year, we think the stock is fully valued," he added.
Google shares traded lower on Monday, while Facebook traded sharply higher.