The Rossoneri's late 2-1 win at Lazio last week, coupled with rival Inter Milan losing to Bologna on Thursday (AEST), leaves Pioli's men two points clear at the Serie A summit with just four games remaining.
Milan is unbeaten in its past 12 league matches – winning seven of those and drawing five – ahead of Sunday's potentially difficult clash with Fiorentina, which is aiming for its first Serie A double over the Rossoneri since 2000-2001.
Speaking ahead of that encounter, Pioli said Milan was fully focused on the threat posed by the Viola, and said his team would need to display its character to end the season as champion.
"It will be a vital game, as will all of our remaining matches," he said. "The best thing for us is to just focus on our next game, as we have always done.
"This has been our biggest strength. Fire in our hearts and ice in our veins.
"We're not thinking about our last four games but just about Milan versus Fiorentina. The boys have been focused, determined and generous throughout the week, which we need going into tomorrow's game.
"Every point is important at this stage of the season. A lot of games will be decided by individual moments, and you need to make these moments swing in your favour."
Milan has conceded only eight goals in 15 league games since the turn of the year, with only quadruple-chasing Liverpool (six Premier League goals conceded) boasting a better defensive record across the top five European leagues in 2022.
The Rossoneri were not considered title favourites at the outset of the campaign, but while Pioli was pleased with how his "energetic" side had emerged as a challenger in a competitive season, he demanded it improves after falling behind in last week's dramatic win over Lazio.
"We're concentrating on doing our job well. It's not time for words, but for actions. I never say that everything will go well, we just hope it goes the way we want," he added.
"I'm not bothered if people outside the team think we deserve it. The important thing is what we are doing; we've overcome various obstacles and we've never been down.
"We have our limits which we are trying to break and we have some assets that need to be praised. We play energetic football, which will always make it easier to win.
"The objectives of a few teams have changed a few times throughout the course of the season; things change quickly. Serie A is a tough league with a lot of good teams.
"We need to improve our approach to games because we got it wrong ahead of the derby in the Coppa Italia [a 3-0 semi-final loss to Inter] and against Lazio. We've worked on that and we're trying hard to limit this type of error."
Milan will hope to continue its fine goalscoring record against Fiorentina on Sunday, having scored at least two goals in each of its past three league games against the Viola, not recording a longer such streak since a run of six between 1992 and 1996.