Ancelotti, Real Madrid's head coach, was furious with Ramos over the defender's first-half expulsion on Wednesday in the UEFA Champions League and the 54-year-old Italian has made it clear he expects better.
Ramos saw red for bringing down Umut Bulut early in their clash in Turkey, although it had no affect on the result as Real went on to win 4-1.
But the ease of the victory did not appease Ancelotti, who was critical with some of his side's defending and their discipline, especially that of Ramos.
"The match was made more difficult by the Sergio Ramos sending off," Ancelotti told Canal Plus.
"I told him (Ramos) he didn't need to take the risk of trying to play for offside; that he had to cover behind him. The danger is always behind, not in front.
"I don't think the defenders should be taking risks, all they need to do is cover behind them and nothing more.
"We suffered a sending off because of that and also for the Galatasaray goal when we didn't cover our backs properly.
"I have told the defenders many times that they have to cover behind them and I don't need to say it again."
The 27-year-old Spanish international has now been sent off 17 times, the most by any player in Real Madrid's history.
Ramos will need to improve that statistic and Madrid's defensive record if they are to continue to challenge for both the La Liga and Champions League crowns.
While the Spanish giants have had no trouble finding the back of the net this season, they have only managed four clean sheets in 20 games in both competitions.
