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 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.
Lacazette's strike - following a fine assist from Bukayo Saka - was his third goal in as many games in all competitions, leaving Arteta to praise the match-winning cameo.
"I think this is what all the managers dream of - to bring people from the bench and to win you the game like he's done tonight," said Arteta.
"He has been in really good form in the last few weeks. He has been scoring goals, he's full of confidence. I think it was a brilliant goal."
Arteta admits the successive victories will give his players a much-needed boost going into the new year.
"In this period, we know how much we needed the wins," said the Spaniard.
"We had a really tough week and it wasn't that much about the performance, it was about the result.
"You need the results to start confidence and now with two wins I think everyone is in a much better mood.
"We have managed through this period to maintain our team spirit and our cohesion, and that is not easy to do because obviously the frustration that comes out with defeat is normally affecting the team."
Brighton stay two points above the bottom three after ending the calendar year with just a solitary top-flight success to show from 17 home fixtures.
Albion boss Graham Potter said: "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.
"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."