NEW YORK — Best Buy Co. reported fiscal third-quarter results that blew through analysts’ expectations as the nation’s largest consumer electronics retailer enjoyed surging demand for items like home theater and appliances that help people learn, cook, work and connect in their homes during the pandemic.

The Richfield, Minnesota-based retailer, said that third-quarter profits rose 33% while sales were up 21%. Sales at stores opened at least a year rose 23%, while online sales in the U.S. surged 174%.

Still, shares fell 5% in Tuesday morning trading as Best Buy warned that sales could slow down during the current quarter as the number of virus cases surge.

“As we start the fourth quarter, the demand for the products and services we sell remains at elevated levels, but similar to last quarter, it continues to be difficult for us to predict how sustainable these trends will be,” Matthew Bilunas, Best Buy’s chief financial officer, told analysts during the call. “In fact, we are seeing COVID cases surge throughout the U.S. and Canada at a time of significant holiday volume through our stores, online and supply chain. “