They were far from their best against Spezia but two goals from Rafael Leao helped Milan on their way to all three points.
Milan extended their 100 per cent start to the Serie A season with a 3-0 win over newly-promoted Spezia at San Siro on Sunday.
Six players kept their places after Thursday's penalty shoot-out win over Rio Ave in the Europa League, and a lack of freshness was apparent in the first half, with Milan struggling to break down their less illustrious opponents.
They looked sharper at the start of the second period, though, and duly went ahead shortly before the hour mark when Rafael Leao prodded home from close range.
Theo Hernandez added a second in the 76th minute before Leao made sure of all three points with another predatory strike two minutes later, as Milan made it three wins from three.