Radja Nainggolan is proving to be one of the best midfielders in Europe this season and he reinforced that reputation with two stunning goals in Roma's 3-1 win at Inter Milan in Serie A on Sunday.
Nainggolan has now scored five goals in his last four league matches.
Mauro Icardi, who was returning from a two-match ban, pulled one back for Inter but Diego Perotti converted a penalty to secure matters.
It kept alive some hope for Roma's title chase as it remained seven points behind league leader Juventus. Roma moved five points above third-placed Napoli, which lost 2-0 to fourth-placed Atalanta on Saturday.
Roma faces a difficult week ahead as it hosts Napoli on Saturday, three days after the first leg of its Italian Cup semi-final against city rival Lazio.
"We're showing we deserve our position," Nainggolan said. "We played against a top team, in a stadium where it is difficult to win but the three points are deserved. Juventus continues to win but we continue to believe and at least we've opened up a little gap over Napoli ... I'm scoring goals, but I am just one player, without the team behind me I would not be performing like this."
Inter is sixth.
"This defeat is a setback we didn't want," Inter coach Stefano Pioli said. "We knew our opponent was strong, but we should have stepped up our performance."
It was an end-to-end match at San Siro and both sides had chances in a frantic start.
But Inter's back three struggled more than Roma's defence and Nainggolan gave Roma the lead in the 12th minute when he received the ball on the left flank, cut inside and curled into the top right corner.
Inter was enjoying its best period of the match when Nainggolan pulled the trigger again.
Inter felt a foul should have been awarded against the Belgian international for a push as he picked up the ball midway in his own half but he ran almost to the penalty area before unleashing a powerful effort into the left side of the net.
Inter pulled one back nine minutes from time when Ivan Perisic rolled across the area and Icardi slid in to net his 16th league goal of the season.
However, any hopes Inter had of snatching a point vanished moments later when Gary Medel tripped Edin Dzeko. Perotti cooly stroked the resulting penalty into the bottom right corner.
Sassuolo 0, AC Milan 1
Gianluigi Donnarumma marked his 18th birthday by keeping a clean sheet in a controversial win for AC Milan.
The goalkeeper only turned 18 on Saturday but the match at the Mapei Stadium was his 60th for Milan, which is expected to tie him to a long-term contract as soon as possible.
Considered the heir to Italy's longtime goalkeeper and captain Gianluigi Buffon, Donnarumma has already made two appearances for the Azzurri — the youngest player to do so in modern times.
Donnarumma had little to do but pulled off a good save to keep out Domenico Berardi's deflected effort in the 73rd.
Carlos Bacca scored the only goal of the match in the 22nd minute with a penalty that Sassuolo thought should have been ruled out after the Colombia forward touched the ball with both feet as he slipped when taking the spot kick.
The penalty had been given after Alberto Aquilani tripped Andrea Bertolacci.
Sassuolo had earlier been given an equally soft penalty but Berardi fired his spot kick wide.
The home side felt it should have had two other penalties but their protests were waved away by referee Gianpaolo Calvarese, who also ruled out a Bacca header for offside.
"The penalty they gave us was debatable and honestly it should have been taken again, apart from anything there were two players in the area when it was kicked," Milan coach Vincenzo Montella said. "However, I think even incidents against you should be accepted more calmly."
Milan moved a point behind Inter Milan.
Lazio is right back in the fight for a Champions League spot after beating Udinese 1-0 to move to within four points of third-placed Napoli.
Ciro Immobile scored from the spot in the 72nd after Lazio was awarded a dubious penalty for an apparent handball by Ali Adnan.
Palermo had a 1-1 draw against Sampdoria, although it is still seven points from safety.
Palermo was the only side in the relegation zone to win as Pescara lost 2-0 at Chievo Verona, while Cagliari won 2-1 at Crotone.
Elsewhere, Olivier Ntcham's stoppage-time goal handed Genoa a 1-1 draw against 10-man Bologna.