Carlos Bacca put aside rumours of a training ground bust-up with Vincenzo Montella by ensuring the AC Milan head coach enjoyed a winning return to Sampdoria in a 1-0 victory.
Reports this week suggested that Bacca had a falling out with Montella and the Colombia international was dropped for Gianluca Lapadula at Stadio Luigi Ferraris.
However, Bacca came up trumps off the bench by coolly netting the winner with five minutes remaining to settle Friday's contest.
Bacca, who this week claimed he almost joined Paris Saint-Germain in the transfer window, scored Milan's goal at the end of a flurry of late activity in Genoa.
Sampdoria saw two goals disallowed and the visitors had appeals for a blatant penalty dismissed, while respective goalkeepers Emiliano Viviano and Gianluigi Donnarumma also made fine saves to keep the scores level.
However, despite having the better of proceedings throughout, Sampdoria duly slumped to their second consecutive defeat, with Milan holding firm to secure their second Serie A win under the tutelage of Montella, who departed Sampdoria for San Siro in the close-season.
Lapadula sought to make the most of his opportunity up front and almost marked his full Milan debut with an early goal, but Matias Silvestre made a timely intervention to head away M'Baye Niang's cross.
The home side created the first clear-cut chance, though, with Lucas Torreira's venomous hit bringing the best out of visiting goalkeeper Donnarumma.
Sampdoria went close again when Muriel's drilled cross into the six-yard box almost ricocheted in from Gabriel Paletta's block.
Having weathered the storm, Milan should have taken the lead when Lapadula raced in behind Sampdoria's defence, only to skew his effort over the crossbar.
Muriel remained lively at the other end and the Colombian weaved his way in from the left before teeing up Edgar Barreto, but Donnarumma was equal to the midfielder's strike.
Sampdoria continued to look sharp after the restart, Muriel again the instigator as he combined with full debutant Dennis Praet, but Paletta was well-placed to intervene.
Marco Giampaolo's men were unfortunate not to have the lead with just over 20 minutes remaining as Barreto prodded an effort past Donnarumma, only for the strike to be incorrectly ruled-out for offside.
That chance seemed to provide a wake-up call for Milan, with Bacca - on as a substitute for Lapadula in the 64th minute - forcing a superb save from Viviano, who parried the forward's low shot onto the upright.
Determined not to be outdone by his counterpart, Donnarumma was the hero for Milan soon after, the 17-year-old ensuring Muriel's powerful strike hit the woodwork with a finger-tip stop.
Sampdoria saw another goal disallowed with under 10 minutes remaining - Muriel having handled the ball before thumping home.
And the hosts were soon made to pay for their inefficiency in front of goal, Bacca prodding home after racing onto Suso's neat pass, wrapping up the points for Milan in the 85th minute.
Key Opta stats:
- AC Milan are unbeaten against Sampdoria in Serie A since August 2012 - five wins and three draws for the Rossoneri in the process.
- Sampdoria have lost their second league game in a row after they had won the previous two.
- In their last eight Serie A home games Sampdoria have alternated one game win and one lost.
- AC Milan have won 1-0 in four of the last five Serie A wins.
- AC Milan have failed to fire a single shot on target in the first half for the second Serie A game in a row.
- Carlos Bacca have scored seven goals in his last seven league appearances.