Manchester City manager Manuel Pellegrini last night admitted that Manchester City must now defeat Chelsea at Stamford Bridge on the last day of the month if they are to retain their Premier League crown.
The City manager, who blamed captain Vincent Kompany for the "unnecessary" challenge on Nacho Monreal that led to Arsenal's first-half penalty, saw his team fail to close the five-point gap opened by Chelsea following the leaders' 5-0 victory at Swansea City on Saturday.
Pellegrini's squad flew off to Abu Dhabi immediately after the Arsenal defeat for a five-day training break in the Middle East and with the champions due to face Jose Mourinho's team on January 31, the City boss insisted the game offered them the chance to kick-start their title challenge.
"The game at Stamford Bridge is a very important game," said Pellegrini. "We must close the gap to two points.
"It is a decisive game and I hope we are going to recover and play in the way we have so far, except for this game. We didn't play a very good game. We had a lot of possession, but we didn't have creative ideas to find the space against a team that defended very well, and we conceded two goals from set-pieces."
Arsenal's first-half opener came as a result of Kompany impeding Monreal in the penalty area and, although referee Mike Dean's decision appeared harsh, Pellegrini admitted that his captain's decision to challenge for the ball was his undoing.
"I think it was not a penalty," he said. "But the movement of Vincent was unnecessary. In that moment, the game changed, we were nervous after the goal, but I don't want to have the excuse of the penalty."
The absence of Yaya Touré, on duty at the African Cup of Nations, does seem significant. The club have won none of their last four Premier League games without the Ivorian.
"Yaya is a very important player," Pellegrini said. "Maybe at the beginning of the season, when we were not playing well, you say Yaya should be out of the team but I never have excuses."
Arsenal's victory - their first league win away from home against the reigning champions since May 2002 - moved Arsene Wenger's team up to fifth, one point adrift of fourth-placed Manchester United.
Despite the potential significance of the win at the Etihad Stadium, Wenger insisted that it was too early to assess the full importance of the victory. "Time will tell," he said. "What is for sure is that it increases the amount of belief and confidence. The five months in front of us are very important in the lifespan of our team and they will determine our season.
"The difference for us now is that we have injured players back that were out for a long time and as well we know it is a very important period. The confidence of the team is high and some players are in good form.
"When we scored the first goal it was easier for us to control the game and we looked always dangerous when we won the ball. We had good solidarity and compactness.
"The regret is we didn't always take advantage of the situations we created in the final third because we had opportunities to score more goals."
Sky pundit Gary Neville last night said that the result called into question whether City had "got it".
He said: "There's a bigger question with City. When you win the league, you have to show progression and grow.
"This team has been together for three or four years and in these next few weeks I think it's now or never for them. For the money they've invested, they're going to want back-to-back titles.
"Against Chelsea and Barcelona (in the Champions League next month), if you fail those games and fail to retain the title this season, you have to ask whether this team has got it." (© Daily Telegraph, London)