Grealish had jokingly promised to pay the Liverpool defender £500 if he scored the free-kick awarded England.
Alexander-Arnold responded by curling in a stunner that helped the Three Lions win the match.
“I said, as a joke, if you score this, I’ll give you 500 quid – and he just slapped it in the top bin. I owe him,” Grealish shared with ITV.
Grealish had opened the scoring for England in the first half, with Alexander-Arnold doubling the lead before Ollie Watkins set up Declan Rice for the third goal.
However, Finland grabbed a late consolation through Arttu Hoskonen.
