Rennes are up to third in Ligue 1 after an Ousmane Dembele double helped them to a 3-1 win over Reims.The home side were 2-0 up after 15 minutes. First Kamil Grosicki converted Giovanni Sio's cross from 15 yards on 12 minutes before Grosicki set up Dembele for his first three minutes later.A mistake from Rennes goalkeeper Benoit Costil allowed Reims to pull one back on the hour through Aissa Mandi.However, Rennes made sure of victory on 67 minutes through Dembele, who cut in from the right before unleashing a left-footed shot into the far corner.