Paris Saint-Germain lead Ligue 1 on 74 points and play Metz on Saturday, while second-place Monaco have 63 points with nine games remaining, seven ahead of Marseille prior to their trip to Toulouse on Sunday.
Monaco striker Radamel Falcao returned to the squad after a month on the sidelines but stayed on the bench as his stand-in Stevan Jovetic showed expert timing to nod home the opener from a Djibril Sidibe cross after five minutes.
But with a huge bank of supporters cheering them on at the Stade de la Meinau, Strasbourg came back at Monaco and Stephane Bahoken's equaliser owed a great deal to his lightning reactions as he produced a snapshot for his fifth goal of the season.
But the in-form Lopes dragged his side ahead again within two minutes by scoring his eighth goal in the past nine matches, and after Fabinho lashed in the third on 41 minutes the contest never looked in doubt.
Sidibe shone on the right and looks a good bet for a place in Didier Deschamps' World Cup squad, as did former Arsenal target Thomas Lemar, who deployed in a deeper role behind the front three played the ball around well from the heart of the action.
"For the moment I'm concentrating on my club form and if that means I play for France too, even better," Lemar told French TV after the match.
Monaco coach Leonardo Jardim said the decision to leave Falcao, his team's leading scorer with 17 league goals this term, on the bench was in the Colombian's best interest.
"Radamel has only trained with the group for four days, he's not at 100 percent and we were leading 3-1 so it wasn't worth taking a risk on this tricky pitch," Jardim explained.
"The most important thing is that he's back training, that he gets back to his level and he will be playing again soon."
Monaco will hope the striker is back at his best to face PSG in the League Cup final at the end of the month.