Arsenal manager Arsene Wenger believes his side emerged successfully from a crucial mental test as they came from behind to beat 10-man Premier League leaders Leicester at Emirates Stadium.
Substitute Danny Welbeck scored an injury-time winner on his first appearance since April 2015 after Jamie Vardy's disputed penalty put the Foxes ahead before Theo Walcott equalised.
Now two points behind Leicester, Wenger said: "It was a serious mental test because we found ourselves 1-0 down against a team that defends so well."
Wenger celebrated on the touchline at the end while the Gunners players mobbed the returning Welbeck.
And the Gunners manager added: "We came back with relentless energy and took all the risks because we knew a draw wasn't good enough. It was down to our mental desire.
"It was a big mental hurdle for us because we were in shock at being behind at half-time. We didn't see that coming. It is not a coincidence Leicester are top.
"This strengthens our belief that we are in the fight. It would have been massive for us to lose because we would have been eight points behind and that is three games for us to win while Leicester would also have to lose three."
Welbeck the hero
Welbeck's dramatic entrance came after two days in training that convinced Wenger he was fit enough for a place on the bench following knee surgery.
The manager said: "It was a great decision in the end because Danny Welbeck is a great player and everybody is extremely happy for him because he has been out for 10 months.
"He has worked very hard with our fitness team to come back so strong and he got a great reception from the other players in the dressing room. He is a great guy with a great mentality."
Ranieri angry - but it's holiday time for Foxes
Leicester manager Claudio Ranieri felt referee Martin Atkinson had been "a little bit severe" on his side.
The Italian was still so pleased with his table-topping team, however, that he has given them a week off - with the club not in FA Cup action next weekend.
He said: "If I look at the game, I am angry because he gave two yellow cards for two normal fouls by Danny Simpson and the match was full of fouls. Maybe the crowd push and put him under pressure after the penalty. The referee was OK - but maybe a little bit severe on us.
"The players asked if they get nine points from our last three games could they have a week away? Now it is just six points but I am still so happy I told them to go away and we will see you next Monday.
"They gave a fantastic performance with a lot of force, soul and helping each other. I told them 'it's OK - we are still top.'"
Welbeck gets trending
From the moment Welbeck scored Arsenal's late winner, the England striker was trending in the United Kingdom. Former team-mates, ex-players and the public tweeted on what could prove a decisive moment in the title race.