Lazio was beaten at home by Chievo on Saturday but Serie A leader Juventus failed to take full advantage of the slip.
Juventus could only draw 1-1 with Genoa, meaning its advantage over the third-placed Lazio is six points rather than the eight it could have been.
Genoa was reduced to 10 men when Antonio Floro Flores limped off the field with an injury, but all three substitutions had already been made. There was nothing else the Rossoblu could do but get all 10 men behind the ball and try to defend the remaining 15 minutes.
The Bianconeri threw everything they could at them, and they had a strong appeal for a penalty waved away when Mirko Vucinic had his shirt tugged inside the penalty area.
Sebastian Giovinco curled a free-kick against the left-hand post, but Juve simply could not find a way through.
With 20 seconds of the game remaining, Juve had another penalty appeal turned down by the referee when Granqvist handled involuntarily in the area, prompting furious scenes with Juve coach Antonio Conte racing on to the field to confront the referee at the final whistle, but Genoa had the point it was looking for.
Earlier in the day, Alberto Paloschi sealed a smash-and-grab 1-0 win for Chievo, who needed just one sight of goal to snatch the points against a wasteful Lazio.
Cyril Thereau got to the goal line and pulled the ball back for Vacek, who was only on the field due to an injury to Gennaro Sardo. His shot struck the underside of the crossbar and fell to Paloschi, who slotted it in from close range.
Lazio tried to salvage a point but nearly conceded a second in the last minute when Seymour was denied by Federico Marchetti at his near post.