The bricks-and-mortar electronics chain on Tuesday said its U.S. online sales grew 23.7 percent during its fiscal second quarter, marking the second straight quarter of nearly 24 percent growth.
That rate of expansion comes on top of a 17 percent lift in the prior-year period, and outpaced growth in the broader e-commerce industry, according to the Commerce Department.
Best Buy's digital sales, which account for 11 percent of its revenue, helped the retailer deliver a surprise lift in comparable-store sales for the quarter, as it reported more measured gains in consumer electronics, computing and mobile phones, and appliances.
The company's shares shot 18 percent higher in afternoon trading.
"That's one of the best e-commerce growth rates for the entire retail industry," Barclays analyst Matt McClintock told CNBC. "That actually says that Best Buy is relevant online, that Amazon potentially isn't as big of a threat as people think for Best Buy as maybe it is for a Target or a Wal-Mart."
Best Buy CEO Hubert Joly attributed the company's digital sales growth to faster and more narrow delivery windows, a speedier checkout process, better navigation and more relevant product recommendations.
Yet he emphasized that the company's stores — once viewed as showrooms that would send shoppers to Amazon to complete their purchase — are a "key asset" in allowing Best Buy to stand out from the competition.
"It's quite intertwined," he said.