Manchester United defender Nemanja Vidic insists the bitter memories of last season's collapse in the title race will stop Manchester United taking anything for granted as they look to regain the Premier League crown. Alex Ferguson's team gifted the title to Manchester City after squandering an eight-point lead in the space of four matches at the end of last season and the pain of that meltdown is still felt at Old Trafford. After rupturing his cruciate ligaments in December 2011, Vidic was a frustrated bystander when United went to Sunderland on the last day of the season. United won 1-0 and briefly thought they were champions as news filtered through from Eastlands that City were losing 2-1 to QPR, but Roberto Mancini's team scored twice in stoppage-time to snatch the title on goal difference. With United now 15 points clear of second-placed City, even Mancini admits the title race is over, but Vidic refuses to start thinking about holding the trophy. "You are never sure until you have the trophy in your hands," he said. "I do think about last season. It is still fresh. "If we hadn't experienced that people would be saying it is already done. But that kind of thing keeps you sharp. "It is good for the team and the players because we don't want that to happen again. It was bad last year but this year it is working for us." Vidic finds it difficult to believe United could have established such a position of strength with nine games of the campaign remaining and the Serb is determined not to let complacency creep in. "We didn't expect this situation. No-one expected it," he said. "We are happy with it but we still have big games to play. "We have to play City, Arsenal, Chelsea, West Brom, Swansea. They are teams who can hurt you. They are tough games. "Teams at the top and some who are fighting relegation. We just have to keep winning."