Netflix's blowout earnings weren't enough to convince one analyst that there's much upside left on the entertainment streaming giant's stock price.

KeyBanc actually lowered its view on the company a day after Netflix reported earning per share of 89 cents, way ahead of Refinitiv estimates of 68 cents. The company saw nearly 7 million new subscribers in the third quarter and projected another 9.4 million in the fourth quarter.

That was enough to send shares up more than 15 percent at one point, though the gain had cooled to about 10 percent in Wednesday's premarket trading.

Still, KeyBanc analysts said they would have preferred to see more profit growth opportunities, instead of just subscriber growth.

"While we remain positive on Netflix's opportunity to grow subscribers and revenue, we believe revenue growth and accelerating margin expansion are needed to drive substantial upside from here," the firm wrote. "The latter has not developed at a pace that exceeds our expectations, which suggests upside is more limited."

KeyBanc cut its view on Netflix from overweight to sector weight. The analysts' price target of $377 suggests a decline from current levels of about $379.50 per share.