Milan boss Fonseca: 'It's never a good time to face Atalanta'
Atalanta are unbeaten in the league since a 3-2 defeat to Como in late September, and are second behind Napoli. They have earned more than 30 points after 14 games played in Serie A for the first time in their history.
The reigning Europa League champions have plundered a league-high 36 goals, while Opta's supercomputer hands them a 28.2% chance of going on to win the title.
Milan, meanwhile, beat Empoli 3-0 last week before hammering Sassuolo 6-1 in the Coppa Italia, meaning they go into the clash on top form.
"It's never a good time to face Atalanta," said Fonseca.
"We are in a good moment, we are growing and we are confident. However, facing Atalanta is always difficult.
"They have won their last eight games, scoring 26 goals and conceding only four. It will be a very difficult match, but we are ready to play it with confidence.
"I think we have prepared the match well. It will be tactical.
"It's very easy to understand how Atalanta play. But it is difficult to counter them, because they do it very well, offensively and defensively."
Milan are seventh, 10 points adrift of leaders Napoli, but Fonseca thinks they are heading in the right direction.
"I think a lot of this comes from how the team defends, because that brings stability and confidence to everyone," Fonseca said.
"The team is doing well defensively and that brings confidence to attack.
"It will be a good test for us, because Atalanta are really strong offensively, they create a lot. It will be a good test to see how we defend and also how we attack," Fonseca added.
Fonseca went up against Atalanta boss Gian Piero Gasperini four times in Serie A during his time at Roma, losing three of those encounters and drawing the other.
"I have no special desire to beat Gasperini," Fonseca said.
"I am the first to say that he is unique. We must recognise the work he is doing. I have great admiration for him. I want to win tomorrow like against anyone."