AC Milan manager Stefano Pioli has demanded his players "raise the level" after their Serie A title pursuit suffered a setback with an emphatic 3-0 home defeat to Atalanta on Saturday. Milan are Serie A's winter champions – a ceremonial award for the table toppers at the halfway stage of the season – and it usually provides a decent indication for the rest of the campaign as 69 per cent of winter champions have gone on to clinch the scudetto. However, Milan will need to ensure the performance against Atalanta is not repeated too often for the rest of the season if they are to win the title for the first time since 2011. "We know what our qualities are and we know that we must raise the level," Pioli told Sky Sports. "The other teams are very strong. We're aware of our strengths and weaknesses and we can still improve." Milan are two points clear of Inter Milan at the summit, but the 3-0 humbling at home to the Bergamo side was their heaviest defeat of the season. "Atalanta's merits are evident, as is the fact that we can do a lot better," Pioli said. "On some occasions we lacked a bit of precision and personality. On the first goal we could've marked better and intercepted the cross earlier. They were better, but we're still a strong side." Atalanta manager Gian Piero Gasperini was thrilled with his side's rise to fourth place, seven points behind Milan. "For the timing of it and the quality of the opposition I think it was the best Atalanta of the season," he said. Gasperini's side have picked up 36 points from their opening 19 games, a club record, but the 62-year-old would not be drawn into talk of a title challenge. "We want to be in the group at the top of the table, among the teams fighting for the Champions League," he said. "This is our main objective. If you're wanting to put the word 'Scudetto' in my mouth you won’t manage."