Dimitri Payet scored in the 89th minute of the game in order to leave OM with a chance of qualifying for Europe, although they will also need a positive result against Lille if they want to push for a qualification spot.
"It's never easy to win at the Mosson, but this second win in a row lifts the tension," said Gignac, according to Ligue1.com.
"We were combative and we won by playing simple football. I hope we can do the same thing in the huge match waiting for us next weekend against Lille.
"We scored three goals and we'll do our best to give our fans an excellent end to the season and qualify for Europe."
The victory currently sees Marseille sitting in sixth position in the Ligue 1 table.