Alexandre Lacazette, Rachid Ghezzal, Jordan Ferri and Claudio Beauvue all scored as OL moved up to sixth in the table with 29 points from 20 games.
Lyon are 25 points behind runaway leaders Paris St Germain, who beat Bastia 2-0 on Friday.
Troyes, who scored through Fabien Camus after the break, have eight points and look doomed, 11 points from safety.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Angers moved up to second on 34 points after beating visitors Caen 2-0, pushing Monaco down to third on 33 as the team from the principality were held to a 2-2 home draw by promoted Gazelec Ajaccio,
France striker Lacazette opened the scoring after 18 minutes with a cross-shot after being set up by Clement Grenier.
Camus levelled in the 67th minute with a missile of a drive from 25 metres.
Ghezzal curled in a delightful shot five minutes later before Ferri, like his team mate, also found the top corner nine minutes from time.
Lyon made it 4-1 thanks to a Beauvue header two minutes into stoppage time.
On Sunday, recovering Olympique de Marseille take on En Avant Guingamp (2000MGT).
(Reporting by Julien Pretot; Editing by Alan Baldwin)
