Apple's iPhone X had a strong showing during its debut quarter as the overall smartphone market slowed, according to new data from research firm Counterpoint.

On Tuesday, Counterpoint said Apple's tenth-anniversary iPhone accounted for 21 percent of total industry revenue and 35 percent of profits during the fourth quarter of 2017. That's quite impressive, given that the handset was only available for two months during the quarter; it was released on Nov. 3.

In a statement, Counterpoint Research Analyst Karn Chauhan said the iPhone X's share of the market "is likely to grow as it advances further into its life cycle."

Meanwhile, "the longer shelf life of all iPhones ensured that Apple still has eight out of top 10 smartphones, including its three-year-old models, generating the most profits compared to current competing smartphones from other [original equipment manufacturers]," Chauhan added. In other words, Apple's iPhone 6 and 7 are bringing in more money than some newer Android flagship smartphones.

Apple grew 1 percent year over year during the quarter, capturing 86 percent of the total smartphone handset market's profits. As for the overall global smartphone market, profits declined 1 percent.

"We believe that the global smartphone market has already reached its peak with longer replacement cycles and key smartphone OEMs are now under pressure to book profits," Counterpoint wrote in a news release.

The iPhone X earned an "excellent" rating in PCMag's review, nabbing props for fresh design, "powerful processor," "excellent screen," augmented reality features. "Like the best Apple products, it dares to question old assumptions, break rules, and introduce radical new concepts," PCMag's Lead Mobile Analyst Sascha Segan wrote.