The two World Cup soccer matches on Thursday in the so-called Group of Death bracket that includes the U.S. gobbled up more Internet bandwidth than any other live sporting event, said Akamai Technologies Inc.

The two games—the U.S. versus Germany and Portugal versus Ghana—drew more than six terabits of data per second, suggesting more than 3.5 million viewers tuned in over the Internet at the same time, according to Akamai, which distributes video over the Internet on behalf of most of the broadcasters with rights to the FIFA...