MOSCOW — Russia welcomed the world to its World Cup on Thursday with a quick, energetic opening ceremony that featured a giant firebird made from crepe paper, English pop singer Robbie Williams flipping off the cameras, a lot of juggling and a speech from President Vladimir Putin.

Russia’s national team then provided a historic encore, blowing out Saudi Arabia 5-0 in one of the most lopsided World Cup openers ever.

Efforts to downplay the enthusiasm afterward went largely unheeded.

“It’s just the beginning, not the end,” Russia coach Stanislav Chershesov cautioned through an interpreter. “We should turn the page and forget this game. We should concentrate on the next step.”

Chershesov, widely criticized before the tournament, hadn’t even finished his attempt at levity before he was summoned from the postgame news conference to take a call.

“It was the head of state who called me with congratulations,” a smiling Chershesov said when he returned. “He asked me to share his thanks for the team. And he asked me to keep playing like this.”

That could be tough. No Russian team had played like it did Thursday, at least not in a World Cup. The victory was Russia’s first in the tournament in 16 years, and the margin equaled its greatest ever in a World Cup. A win or draw in either of its final two group-stage games could send the team on to the knockout round for the first time since the breakup of the Soviet Union.

This World Cup is the first to be played in Eastern Europe, and Putin, who is hoping the tournament will bring his government international prestige, used his speech to celebrate soccer’s power to provide “a unity which cannot be affected by different language, ideology or faith.”

Chershesov’s team didn’t wait long to reward the faith of its long-suffering fans in the crowd of 78,011. Yury Gazinsky scored in the 12th minute, heading in a long, bending right-footed cross from Aleksandr Golovin.

In a midfield suite, squeezed between the stadium’s upper and lower bowls, Mohammed bin Salman, the crown prince of Saudi Arabia, reached across FIFA President Gianni Infantino to congratulate Putin with a handshake.

With Russia ranked 70th in the FIFA world rankings and Saudi Arabia at No. 67, Thursday’s game was the first World Cup opener to feature two countries ranked outside the top 30. While the teams are nearly even in the rankings, they weren’t on the field.

In the closing minutes of the first half, Denis Cheryshev, who came off the bench when playmaker Alan Dzagoev was forced off with a hamstring injury, doubled the advantage with the first of his two goals.

After running onto a through ball from Roman Zobnin in the center of the penalty area, Cheryshev dribbled toward the edge of the six-yard box, and when Saudi defenders Omar Hawsawi and Mohammed Alburayk went for slide tackles at the same time, the Russian flipped the ball over Alburayk and lifted a left-footed shot past goalkeeper Abdullah Almuaiouf at the near post.

“There are no words to express what I’m feeling right now,” Cheryshev said through an interpreter. He had become a forgotten man with the national team, playing just seven minutes for Russia between 2015 and his selection to the World Cup roster last month.

“I’m happy that we won. I’m happy that I was able to help my team,” he added. “I could have never dreamt anything like this.”

Russia kept up the pressure in the second half and was rewarded when Artem Dzyuba, another substitute, headed in another perfectly placed cross from Golovin seconds after coming on in the 70th minute.

Cheryshev and Zobnin closed out the scoring with stoppage-time goals. Igor Akinfeev picked up the shutout without making a save.

Afterward, Cheryshev joined his manager in trying to temper any exuberance.

“We won but we shouldn’t stop here,” he said. “At any moment, when you relax, you can be kicked out. ... To be good is one thing. To be good at the right place and time is a different thing altogether.”

Worst day: Julen Lopetegui said being fired as Spain coach two days before its opening match at the World Cup was “possibly since the death of my mother the saddest day of my life.”

Lopetegui made the remarks at his presentation as Real Madrid coach on Thursday.

Lopetegui was fired by Spanish football federation president Luis Rubiales on Wednesday — a day after Madrid made the unexpected announcement that Lopetegui had agreed to leave the national team for the European club champion.

Rubiales said Madrid and Lopetegui kept him in the dark until five minutes before the club made the deal public.

Associated Press contributed

kevin.baxter@latimes.com