Apple reported earnings per share of $1.42 on revenue of $42.1 billion, easily beating analysts' expectations.
The company also gave sales guidance for the current quarter of $63.50 billion to $66.50 billion, at the high end of current analysts' estimates.
Wall Street expects the firm to hand in first-quarter earnings of $2.39 per share on $63.52 billion in revenue, according to a consensus estimate from Thomson Reuters.
Shares rose more than 1 percent in after-hours trading before easing.
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Demand is "off the charts" for iPhone 6 and 6 Plus, said Tim Cook, Apple's CEO. He noted that the company is "excited by initial results for iPhone 6 in China."
"[W]e are heading into the holidays with Apple's strongest product lineup ever. We are also incredibly excited about Apple Watch and other great products and services in the pipeline for 2015," Cook said.
The company sold 39.3 million iPhones, generating about $23.68 billion in revenue, up 21 percent from a year ago. However, iPad sales declined 14 percent to $5.32 billion, with about 12.32 units sold.
Analysts polled by StreetAccount had forecast iPhone sales to rise to 37.41 million, while iPad shipments were expected to come in at 13.37 million.
The company's cash pile declined to $13.84 billion, from $14.26 billion a year ago. Its closely watched gross margin rose to 38 percent, at the high end of its previous forecast of between 37 percent to 38 percent.
"Find me a better company out there. It's ridiculous. They have the best products and so much cash they could buy a country," Darren Chervitz of Jacob Internet Fund said.
Analysts had expected the company to report earnings of $1.31 a share on $39.88 billion in revenue, according to a consensus estimate from Thomson Reuters. Wall Street expects the tech behemoth to ship 61.13 million iPhones and 23.42 million iPads in the first-quarter, according to StreetAccount.
Apple has widely outperformed the Nasdaq and the . As of Monday's close, shares of the iPhone maker had gained nearly 37 percent over the last year, while the Nasdaq and S&P saw gains of 10 percent and 9 percent, respectively.
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"I'm impressed with what they delivered," Paul Meeks of Saturna Capital said. "To play devil's advocate, I'm a little bit disappointed, but not surprised, by the year to year drop in iPad units. But what's happening is the smartphone is cannibalizing the iPad. So over time I want to see iPhones grow very fast and I want to see Apple Pay do well. Those are the growth drivers."
IPhone users are expected to account for about 41 percent of U.S. smartphone users in 2014, while Android users will make up nearly 52 percent, according to eMarketer.
Apple unveiled two new tablets last week, the $399 iPad Mini 3 and the $499 iPad Air 2, as it battles to compete in the increasingly crowded tablet sector.
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Apple's share of the U.S. tablet market will decline to about 52 percent from 55 percent a year earlier, research firm eMarketer predicts. In the U.K., the figure is projected to fall to 53 percent from 57 percent in 2013, eMarketer said.
Apple rolled out its iPhone 6 and 6 Plus near the end of the its fiscal fourth quarter. The sales topped 10 million during the first weekend of availability in the U.S.
Analysts expect release of the new devices in other countries, specifically China, to drive future growth.
Apple Pay, the company's new mobile payments system, launched Monday on the iPhone 6 and 6 Plus as the company looks to gain market share in the fast-growing sector. U.S. mobile proximity payments will surpass $1 trillion in volume by 2017, according to IDC research.
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Over 500 banks and 22,000 retailers, including Bloomingdale's, Walgreens, McDonald's and Duane Reade, plan to support the feature by the end of the year. However, Walmart, the world's largest retailer, and Best Buy will not accept it.
In addition, corporate credit cards, prepaid credit cards and retailer's branded cards aren't equipped to support the technology, which means shoppers could miss out on special discounts, WSJ reported earlier.
For the fiscal first quarter, Wall Street expects the firm to hand in earnings of $2.40 per share on $63.52 billion in revenue, according to a consensus estimate from Thomson Reuters.
—CNBC's Lee Brodie contributed to this report.