Liverpool midfielder Javier Mascherano said he cannot understand why referee Steve Bennett sent him off in the 3-0 defeat at Manchester United on Sunday. Mascherano appeared to have an argument with Bennett when the latter cautioned Fernando Torres for dissent, only to get a second caution himself. "I do not know why I was sent off. I asked the referee what was happening. I did not swear; I was not aggressive and I did not confront him," the Argentine told the Liverpool Echo. "All I did was ask him what was happening, nothing else, when he (Bennett) showed me the second yellow card and sent me off I could not believe it." Mascherano's expulsion meant that Rafa Benitez's team had to play more than 45 minutes with a man down against the Premiership leaders. "I am sorry to my team-mates because that meant we went down to 10 men - and that made things even more difficult for us," he added. The former West Ham midfielder could get a further ban by the FA for failing to leave the pitch immediately after his sending off.