The Gunners battled back from two goals down to draw 2-2 with north London rivals Spurs in their Premier League meeting at the Emirates Stadium.
Alexandre Lacazette and Pierre-Emerick Aubameyang were again on hand to provide the goals after the visitors had taken control of the game courtesy of Christian Eriksen and a Harry Kane penalty.
Eriksen's 50th Premier League goal was a tap-in from close-range after Leno had only managed to palm a Son Heung-min shot into the path of the Denmark international.
Despite his error, Leno went on to make a great save to deny Son and then did well to keep out an Eriksen free-kick and - after rescuing a point, the Germany international insists Unai Emery's side can catch Spurs this year, having finished below them for the past two seasons.
"Today we showed that we can play better than them," he said after the game.
"To be honest in the first half you saw the quality of Tottenham so again it will a very hard fight until the end of the season and then we will see who will be better.
"Some minutes after the game it was a little bit disappointing because we had the chance. But after one hour you have to say it is okay because we were 2-0 down and came back to 2-2 and also that Tottenham had a lot of chances and could have scored the third goal so at the end it was a deserved draw."
Leno went on to praise the character of the Arsenal players and said it was up to him to show his own mental strength to recover from his early mistake.
"I think the first goal was a little bit unlucky," he said.
"I couldn't catch the ball completely and then I tried to get up but Eriksen scored, it was unlucky but that is the life of a goalkeeper.
"For me it was then like the team, I had to stand up. It is not a big problem just because we conceded a goal, I had to stay positive and I thought after that I did a very good job.
"I think it was a very difficult start but then we said as a team on the pitch after going 2-0 down 'we have to stay positive'.
"There was still an hour to play and we know about the character in this team and also our quality and then after it went to 2-1 you could see that we at least wanted to draw the game and at the end we still had the chances to win.
"Everybody was going crazy in the last minutes, all the fans and players were crazy and the referee made the right decision, he just said that everyone should calm down so it was okay."
With Lacazette and Aubameyang on form at the other end of the pitch, Leno feels Arsenal have a forward line that can ensure they outscore the majority of their opponents.
"We know about our character but also about the quality," he said.
"The three players up top, with Pepe also there now, we have unbelievable quality. They can score the big chances but also score from nothing and so the other teams always know and have to be aware that we have a lot of dangerous players and that gives us big confidence.
"You can see the game against Liverpool (a 3-1 defeat) we had one or two chances to score when it was 0-0 so we can score with our quality in that top three.
"We can score against everybody but I think the key is always the balance with the defence because in the end that is the most important thing."
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