Arsenal boss Mikel Arteta hailed a “dream” substitution after Alexandre Lacazette made an instant impact to secure a 1-0 success at struggling Brighton.

Frenchman Lacazette, who was dropped to the bench due to a sore back, recovered sufficiently to clinically claim the second-half winner just 21 seconds after coming on at the Amex Stadium.

Victory on the south coast backed up the 3-1 Boxing Day win over London rivals Chelsea to move the Gunners nine points clear of the relegation zone.

“There was lots to be positive about, certainly first half. I thought we did well in the game against a team that has some good attacking players,” he said.

“Overall the game is quite an even game. We didn’t probably create as much as we would have liked, so we need to improve that.

“It’s just frustrating that we’re not winning or picking up the points we’d like to.

“We’re doing some things well but we need to carry on improving. This league is so demanding, so punishing. These things can happen and we have to stick together as a group.”