Having come on as a second half substitute, Grealish first won a penalty for England before then taking centre stage at the Estadi Nacional with four minutes left.
With England already 4-0 up, our summer signing from Aston Villa registered his first goal for the Three Lions by producing a superb finish after latching onto goalkeeper Sam Johnstone’s magnificent assist.
For Gealish though it was an especially memorable occasion.
"It has been a long time coming and it's about time that I scored because everyone has been saying it to me,” the City winger admitted.
“I think that is 16 games now. It was coming and I'm just delighted that I've got off the mark.
“In the back of my mind there has been that feeling that I've just wanted to score, just to get off the mark.
“Obviously I've done that tonight, I'm delighted and it's a night I won't forget.
“I want to be starting games, to be starting the biggest of games and keep playing for England.
“Luckily over the past few months and during the Euros I've had the chance to do that.”
Ben Chilwell, Bukayo Saka, Tammy Abraham and James Ward-Prowse were also on target as England maintained top spot in Group I with 19 points from seven games.
The Three Lions are in action again on Tuesday when they play host to Hungary at Wembley.