Both sides come into the match after disappointments in the warm-up games and being separated by a mere three points in the FIFA rankings, picking a side between the two can test even the best of football pundits.
Saudi Arabia attempted to continue with their possession-based game in the second half.
So much talk in the lead up to the tournament had centered on whether Russian Federation would be able to match the settings of previous World Cups.
After receiving his Man of the Match award, he said: "There are no words to express what I'm feeling".
The World Cup favorites - Germany, Spain, France, Brazil - enter the fray from Friday onwards.
Russian fans were less numerous than global ones, but were ecstatic as their team pulled off a triumphant start to the championship.
The host nation had the momentum towards the 20th minute and were unlucky not to have found the second goal through their high press.
That the two participating soccer teams harbor no hope of raising the 11-pound, gold-plated trophy at this very same venue four-plus weeks forward did not matter a lick to the 78,011 stuffed inside Luzhniki Stadium, the 25,000 partying in the adjacent riverside fanfest and hundreds of millions watching in time zones near and far. Win it to get out of the group is vital, so there is no doubt - in the national team of Russian Federation will come to the maximum fighting strength.
Saudi Arabia were under increasing pressure and Smolov's deflected strike was clawed away by keeper Abdullah Al-Mayouf when play continued after an offside had been missed.
GOAL! 43rd minute: Substitute Denis Cheryshev gets his name on the scoring sheet doubling his teams lead.
The project to send key midfielders Fahad Al-Muwallad, Salem Al-Dawsari and Yahya Al-Shehri on loan to Spanish LaLiga clubs in January also backfired as they lacked the quality to break into their respective teams and clocked just 58 minutes of playing time.
Alan Dzagoev should anchor the midfield with Golovin and Roman Zobnin, as versatile 22-year-old twins Aleksei and Anton Miranchuk are the wildcards in midfield or attack.
Soon afterwards, Russian Federation were forced into a change when midfielder Alan Dzagoev pulled up with what seemed to be a hamstring injury and was replaced by Cheryshev.
Aleksandr Golovin (Russia) Though it feels harsh not to reward Cheryshev for two lovely finishes, it was Golovin who ran the game.
Of his performance and the team's, he said, "I could never have dreamed anything like this". Russian Federation on the other hand, have done a good job of keeping their hopes of progressing alive. But Saudi Arabia could spring a surprise if they manage to be disciplined throughout the match.
"As for our strategy, we must change".