Arsene Wenger says Arsenal's victory over title rivals Manchester City "strengthened our belief that we can win" the Premier League, the manager said after Monday's 2-1 win.
The three points secured Arsenal's hold on second place and brought them to within two points of leaders Leicester while also putting them four clear of City and the rest of the league.
Wenger warily acknowledged his team's title chances and said his players are growing in maturity.
"It has strengthened our belief that we can win the title. We need to fight like that every game," he said. "We are more mature than before and that shows in the games where we are under pressure.
"We are very ambitious, but you see the Premier League is very difficult. That's why we are very cautious.
"We did very well against City, but we have to do it again on the 26th versus Southampton.
"I don't know when we last had such a good chance to win the title. We have not had such a good chance for a few years. Although we were also top of the league for a while in 2013-14. But we know there is still a long way to go.
"There is a real togetherness. It is a significant game. When you look at Manchester City and their quality we know they will be there in the title race."
Wenger said he was glad with how his team started, with first-half goals from Theo Walcott and Olivier Giroud, but said it was not easy to finish the game after Yaya Toure brought a goal back for City.
"It was a very intense game, with both teams giving everything," Wenger said. "We always looked dangerous. We got great goals in the first half and we became shaky at 2-1.
"We knew how big this game was, Theo Walcott scored a fantastic goal which surprised Joe Hart and it put us on the way.
"Olivier Giroud is influential in every game. We missed chances, that's the fear you have. When you see Wilfried Bony and Jesus Navas coming on you know they can make a difference."
Wenger also told Sky Sports that "spirit" saw his players through when they were holding off City at the end of the 90.
"When we had not the legs any more we relied on the spirit and that got us through in the end," he said. "You could see when the legs went -- [Mesut] Ozil was sick all week -- but they still keep going. That's fantastic to see."
Toure scored with a remarkable effort from a one-two on the edge of the box, softly lofting a shot into the far corner with his first touch, and Wenger had nothing but praise for the Ivorian.
"Yaya Toure, I have known him since he was 15 years old and he can play in every position," Wenger said. "He has scored so many late goals but this one is one of the exceptional ones."