Gerard Deulofeu's first goal for AC Milan boosted the Rossoneri four points clear of Serie A rivals Fiorentina and into a position to pursue European football once again.
The Spanish winger moved to San Siro on loan from Everton in January and has soon found himself performing a key role as a prong in an attacking trident alongside Suso and Carlos Bacca.
It was midfielder Juraj Kucka who scored first in the 2-1 win, with Nikola Kalinic providing a prompt reply for Fiorentina, but Deulofeu's fine strike at the end of a jinking run clinched all three points from a first home triumph in over a month.
Both clubs knew before kick-off that this head-to-head represented the last real opportunity to stake a claim for a top-five finish after indifferent campaigns.
With that in mind, eighth-placed Fiorentina started enthusiastically and, after Josip Ilicic had clipped wide in the opening minutes, teenage goalkeeper Gianluigi Donnarumma was forced into a diving save to repel Borja Valero's left-footed effort.
Milan weathered that storm and bit back with venom. Kucka put the Rossoneri ahead 16 minutes in with a header that met Jose Sosa's free kick and pinged past Ciprian Tatarusanu.
The celebrations were soon quelled, though, as Kalinic grabbed an equaliser only four minutes later, the Croatian reaching 11 goals for the season with a close-range conversion of Federico Chiesa's cross from the right.
A strong suspicion of offside riled Milan and they conjured up the best response shortly after the half-hour mark with Deulofeu breaking his Italian duck in style.
When Valero lost the ball in midfield, the Everton loanee took possession and advanced skilfully through the Fiorentina half before finding the back of the net.
Milan might have extended their advantage heading into the break but Tatarusanu pushed Mario Pasalic's snapshot onto a post.
Fiorentina were first to threaten when play resumed, Valero picking out Carlos Sanchez for a scoop over the bar that he should have kept lower.
For the most part, inspiration had evaporated from the San Siro pitch and it was not until the 85th minute that Milan offered more entertainment.
Andrea Bertolacci fed Ignazio Abate only for Tatarusanu to make a low block, with Sanchez striding across the goal-line to deny Carlos Bacca an easy finish on the tap-in.