Somali referee Omar Artan said the "biggest dream of my life" had been ripped away after he was denied entry to the United States to officiate at the World Cup.

The United States emphatically launched its home World Cup Friday, thrashing Paraguay 4-1 with a perfectly scripted opening performance to delight a star-studded home crowd in Los Angeles.

The World Cup co-hosts know they must avoid a banana skin at the futuristic SoFi Stadium in the first World Cup finals game on US soil for 32 years.

The extravaganza hosted by the United States, Mexico and Canada is the biggest World Cup in history, stretching until the final in New Jersey on July 19.

Serena Williams will take part in her first professional tennis match in nearly four years on Tuesday after organisers confirmed the order of play at London's Queen's Club.