Bordeaux stretched their unbeaten run to six Ligue 1 games with a resounding 4-0 win over Rennes.The hosts took the lead when an unmarked Cheick Diabate headed beyond Benoit Costil.Les Girondins doubled their advantage on 51 minutes, again thanks to Diabate, when the big forward benefited from some poor Rennes defending to fire beyond Costil.And the points were wrapped up when Diego Rolan hammered home a rebound after Costil did well to keep out Adam Ounas' initial effort before Thomas Toure added a fourth in stoppage time with a neat finish from the edge of the area.