Arsenal boss Arsene Wenger admits his side suffered the effects of last summer's World Cup finals at the start of the season.
The Gunners won only one game in September of last year as they struggled for form and suffered back-to-back defeats at the hands of Swansea City and Manchester United in November, days after blowing a 3-0 lead against Anderlecht in the Champions League.
But their excellent form in 2015 saw them move up to second in the table, much to the delight of their manager.
"The target of the work during the season is that your team becomes stronger and we still have many challenges until the end," Wenger said on Thursday.
"It's interesting that we are in good form and it's interesting that we have a good team dynamic. Hopefully we can maintain that until the end of the season, then we will see where we stand.
"We look behind us and people are chasing us, in front of us there's quite a big distance with Chelsea but we work very hard to reduce that. They have a difficult schedule and we have a difficult schedule. What we can only do is master our own schedule.
"What we want is to go as high as we can until the end of the season, give our best and we are also in the semi-finals of the FA Cup.
"We are at an important moment of the Premier League season and it is a period where you show your quality by focusing on the next game and maintaining the quality.
"We had a difficult start this season compared to last year.
"This season we had many players out for four or five months after the World Cup and since we have found our cohesion with everybody back, we feel we have moved forward.
"I just think we are at a stage of the season where we took off in January, because we had nearly everybody available.
"That made us more efficient. We have maybe a better team balance between attacking and defending as well than we had [in the period] until January."