Jack Grealish's dancing World Cup goal celebration for England vs. Iran fulfilled a promise to a young fan

Marcotti impressed by England's devastating performance vs. Iran (2:01)

Gab Marcotti says England can only take positives after an impressive attacking display in their 6-2 win vs. Iran. (2:01)

England got their 2022 World Cup campaign off to a fantastic start with a runaway 6-2 victory over Iran, and it was Jack Grealish who got his team's final goal.

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The Three Lions hit six goals in a match at a second consecutive World Cup, following on from their 6-1 trouncing of Panama at the 2018 finals in Russia.

Grealish had come off the bench at the Khalifa International Stadium in Doha, Qatar to tap home England's sixth goal of the game in the 90th minute, which he celebrated with a jaunty jig.

But the cheeky dance routine isn't a trademark of Grealish's, nor is it a tribute to former England striker Daniel Sturridge, who pulls off a similar move whenever he hits the back of the net.

The 27-year-old busted a move in order to keep a promise to Finlay, a young Manchester City supporter with cerebral palsy who wrote a heartwarming letter to the forward earlier this season. Finlay had written to Grealish after learning that the player's sister, Hollie, also has cerebral palsy.

As a special thank you for the message, the City star wrote back to his 11-year-old fan and sent him a signed shirt. But then, much to Finlay's surprise and delight, Grealish went one step further with a surprise meeting at the Etihad Campus earlier this month.

During their conversation, Grealish promised to perform a celebration for Finlay the next time he scored. The youngster initially requested "The Worm" but had to settle for something with less likelihood of causing injury -- a shimmy coupled with a ripple of the arms.

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Grealish's next goal came not for City but for his country on the biggest international stage when fellow substitute Callum Wilson raced clear before laying England's sixth and final goal against Iran on a plate for his teammate. After finishing the chance, Grealish knew what he had to do.

Posting on social media after the game, Grealish made a point of dedicating both his goal and his celebration to Finlay.

"For you Finlay," the 27-year-old wrote on Twitter.

Finlay really was fortunate that Grealish was able to send the message from the Middle East, as the City forward had only scored one goal all season up to that point.

That goal came in the very first minute of City's 3-0 win at Wolverhampton Wanderers on Sept. 17, so there was something pleasing about the fact that his goal for England came in the 90th minute against Iran.