The 1-0 win that lifted Inter into fifth place was certainly hard-earned at San Siro, with new signing Hernanes and Diego Milito thwarted on numerous occasions by a much-improved Sassuolo backline.
Indeed, the 19th-placed Neroverde conceded six fewer goals than when the sides met in September.
One lapse in concentration was punished late on Sunday night, however, with Samuel duly glancing home the winner from a corner in the 48th minute.
Inter humbled newly-promoted Sassuolo 7-0 in the reverse fixture, an outcome that surprised few at the time given the Nerazzurri were setting the early pace alongside Roma.
The takeover of the club by Indonesian billionaire Erick Thohir in October created more optimism but, on the pitch, the goals dried up and Inter soon began to slide unceremoniously down the table.
Before kick-off here Walter Mazzarri's men were sixth in the table and without a victory in the new year.
Since winning the Milan derby shortly before Christmas, they had scored only one goal at San Siro.
Sassuolo - stuck in the relegation zone and facing an instant return to Serie B - have nevertheless proved dangerous going forward and may well have snatched an unlikely victory through talented young striker Domenico Berardi.
The provincial club that beat AC Milan 4-3 last month threatened Inter within seven minutes, Berardi feeding Aleandro Rosi to fire in a low cross that Jonathan struggled to clear.
The hosts bit back with Fredy Guarin unleashing a powerful drive before ex-Lazio man Hernanes fizzed an even fiercer effort just past a post.
Berardi, who at 19 years old has already scored 12 goals in first season at this level, almost became the architect of the opening goal but his pinpoint free-kick was nodded wide by Lorenzo Ariaudo.
With Sassuolo seizing control, their teenage dangerman took aim himself shortly after the half-hour, Inter keeper Samir Handanvoic only just getting gloves to his left-footed shot on the turn.
Milito should have given Inter the lead before the break, but twice the Argentinian wasted easy chances to do so.
On both occasions he was set up by countryman Rodrigo Palacio, at first from the left wing and secondly from the right, and both times visiting keeper Gianluca Pegolo watched the striker panic instead of sweeping the ball home.
Milito's bout of nerves was promptly forgotten after the interval when Samuel powered home the only goal of the game.
Hernanes delivered the corner and Inter's Argentinian defender was well-positioned to stoop forward and bullet the ball over the line.
Inspired by their captain, the Nerazzurri pushed for a quick-fire second and nearly found it through Guarin, who again screamed one wide, and Jonathan.
The defender showed good skill to control Hernanes' cross but blasted over.
The onslaught continued throughout the final 15 minutes and Pegolo blocked Milito's close-range snapshot before launching himself at a Hernanes volley with Sassuolo in full damage limitation mode and retreating.
There was a rare Neroverde break as time ticked away, which saw substitute Antonio Floro Flores smash Alessandro Longhi's cute pass wide of the Inter goal, but Sassuolo's race was long since run.