The game took a while to spark into life, with neither side finding any attacking fluidity in the first 30 minutes.
Diogo Sousa shot wide after 10 minutes, while Giovanni Reyna saw his header saved shortly after for the home side, but that was as good as it got.
However, just after the half-hour mark, the game received the boost it needed as the Red and Blacks took the lead when Przemyslaw Frankowski’s pass into the area found Boulaye Dia unmarked, and the forward’s first-time finish rippled the net.
Not only did that strike put Le Racing on the back foot, but it also means they have now failed to keep a clean sheet in any of their last 16 Ligue 1 matches.
Dia was unbeaten in his last 29 goalscoring appearances for club and country, and that run looked even more likely to continue when his team doubled their advantage four minutes before half-time.
Mahamadou Nagida’s ball across the area found its way through to Sebastian Szymanski, whose well-struck first-time finish flew past Filip Jorgensen and into the net.
The away side knew they needed to strike early in the second half to give themselves a realistic chance of getting back into the contest, but they instead found themselves further behind with a little more than an hour on the clock.
Szymanski netted his second goal in stunning fashion, receiving the ball 25 yards out before unleashing a left-footed curling effort that went in off the underside of the crossbar to put the game to bed.
The visitors failed to register a single shot on target in the second half in what was a very lacklustre display, allowing their opponents to stroll to victory.
Le Racing have now lost four successive matches in Ligue 1, leaving them in the relegation play-off spot.
The jubilant Red and Blacks, on the other hand, leap six places to the summit, also extending their unbeaten run at home to an impressive nine matches.
Flashscore Man of the Match: Sebastian Szymanski (Rennes)
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