NEW YORK -- An estimated 21.6 million people watched Belgium knock out the United States in the World Cup on U.S. television -- an impressive total for a weekday afternoon that almost certainly undercounts how many people actually saw it.

The Nielsen company said Wednesday that 16.5 million people watched the game on ESPN, with 5.1 million more seeing it on the Spanish-language Univision network. In addition, nearly 1.7 million people watched an online stream of the event, Nielsen said.

- Torre: Hey America, where are you going?

The record U.S. television audience for soccer is the 24.7 million who saw the United States play Portugal on June 24, which tied the 2010 World Cup final between Spain and the Netherlands.

The Portugal game took place on a weekend, however, when there were more people with free time available to watch. The U.S.-Belgium game started at 4 p.m. on the East Coast, earlier in other time zones, during a working day.

Nielsen does not measure viewership in bars, offices or other public places. In 2010, ESPN estimated that the stated audience size for weekday World Cup games would increase by 23 percent if public viewing were taken into account.

Still, Tuesday's knockout game exceeded the average viewership for the most recent World Series and NBA Finals, events that took place during prime-time when more people were home to watch.

The just-concluded NBA Finals where the San Antonio Spurs beat the Miami Heat averaged 15.5 million viewers, with 18 million watching the final game. Last fall's World Series averaged 14.9 million viewers, with 19.2 million watching the Boston Red Sox beat the St. Louis Cardinals in the last game.

The TV ratings for the U.S.-Belgium World Cup match do not include the 28,000 people who watched at Soldier Field in Chicago. Timothy Hiatt/Getty Images

U.S. coach Jurgen Klinsmann said on Wednesday that everyone connected with the soccer team is excited to see how the sport is reaching a U.S. audience. He could see it coming, given the popularity of the game among young people and the large crowds that turned out for the team's sendoff games before the World Cup.

"Soccer is breaking through and gets its deserved recognition without taking anything away from the other big American sports," Klinsmann said.

He said it's important for people to identify with the way Americans played the game.

"The energy and the commitment and the tempo and the aggressiveness that we played with kind of made people proud at home and surprised a lot of people outside of the United States, maybe in Brazil or in Europe," he said.

The highest overall ratings for the U.S.-Belgium game came in New York, Nielsen said.

ESPN said that overall viewership for the World Cup is up 44 percent over 2010.