Russian President Vladimir Putin officially opened the World Cup on Thursday at a ceremony in Moscow's 80,000-seat Luzhniki Stadium.
Minutes before Saudi Arabia kicked off the tournament against host nation Russia, Putin said: "I congratulate all of you at the start of the most important championship in the world."
"Love for football unites the entire world in one team, regardless of people's language or ideology," Putin said to thunderous cheers from the capacity crowd.
He said Russia had approached preparations for the most-watched event in the world "responsibly, doing everything to make sure fans can enjoy this celebration."
"This grand sporting event is taking place in Russia for the first time, and we are truly happy," he said.
"In our country, football is not just a popular sport, not just the most beautiful sport -- people here truly love it," the Russian leader said.
The opening ceremony included a mini-concert by British pop star Robbie Williams, who performed "Let Me Entertain You".
Russia has left no stone unturned preparing for its most important event since the 1980 Moscow Summer Olympics, spending more than $13 billion (11 billion euros) on infrastructure in the 11 host cities.