The Toffees will face Premier League rivals City in the first leg of the League Cup semi-final tie at Goodison Park.
Former Everton striker Gray has predicted that the Merseyside outfit will win the game.
“The last five or ten minutes of the Watford game was an amazing spell of play for Manchester City,” the former Scotland international has written on Paddypower.com.
“Somehow they dragged themselves through that game and managed to take all three points but if Everton get on the front foot early then Romelu Lukaku can trouble Mangala, who struggled against Ighalo. City aren’t back to their best and Lukaku could be the difference maker.”
A footnote added: “Andy’s bet: Lukaku to score and Everton to win.”
Everton will head into the match against City on the back of a 1-1 draw with Tottenham Hotspur at Goodison Park in the Premier League.
The Toffees are struggling to win games at the moment, although their football is not bad.
Roberto Martinez’s side are brilliant to watch going forward and are very pleasing to the eye, but defensively they are vulnerable.
City have arguably the best strike-force in England and will score at least once at the Goodison on Wednesday evening.
If Manuel Pellegrini plays his strongest available team, then the Citizens should be considered as favourites to win the first leg.