Manchester United turned up the heat on Premier League leaders Liverpool and manager Rafael Benitez as they closed the gap at the top of the table with a convincing win against Chelsea at Old Trafford.Nemanja Vidic headed United in front in first half injury-time after Dimitar Berbatov flicked on Ryan Giggs' corner.Wayne Rooney then turned in Patrice Evra's cross after 63 minutes to set United on the path to a deserved three points - leaving them five points behind Liverpool with two games in hand.Berbatov rounded off the win by grabbing the third from close range four minutes from time, turning in Cristiano Ronaldo's free-kick as United's fans finally sensed their title charge was hitting top gear.Sir Alex Ferguson will regard the victory as the perfect response to public taunts from Liverpool counterpart Benitez that United may be "a little bit scared" at the sight of their great rivals at the Premier League summit.United were not at their free-flowing best in a game that was too stop-start to be of the highest quality, but they showed none of the fear Benitez might have been hoping to detect.And if this weekend was the start of psychological warfare between Benitez and Ferguson, there is no doubting that it is United's boss who has taken the first round.They were vastly superior to a Chelsea side that lacked a cutting edge, despite coach Luiz Felipe Scolari pairing Nicolas Anelka and Didier Drogba together up front after the break.It may also make Benitez question the timing and content of his tirade against United and Ferguson - who appeared inspired rather than deflated by the remarks coming from down the East Lancashire Road.For Scolari, it was a sobering afternoon when he received further confirmation that he needs to inject threat, particularly in the shape of more width, into his Chelsea side.Former Chelsea boss Jose Mourinho watched from the stands in readiness for Inter Milan's Champions League clash with United. He will have been dismayed at how Chelsea failed to trouble Edwin van der Sar and ended up losing so lifelessly.Ferguson sprang a selection surprise by leaving Michael Carrick on the bench and choosing to go with veteran Giggs in midfield, while Drogba was handed Chelsea's lone striking role.Referee Howard Webb was in the spotlight after Benitez's blast about Ferguson and officials - and he showed his intent to clamp down quickly with a third minute booking for Frank Lampard after he fouled Ronaldo.It set the tone for a scrappy first 45 minutes that only truly burst into life in the closing stages as United finally exerted a measure of supremacy.Giggs tested Petr Cech with a powerful free-kick that Chelsea's goalkeeper pushed to safety, before referee Webb produced another flurry of yellow cards.He booked Chelsea's Jose Bosingwa for a foul on Rooney, quickly followed by Portugal team-mates Ronaldo and Ricardo Carvalho for a penalty area clash.Berbatov has yet to win the hearts and minds of Manchester United supporters, and they were frustrated when he wasted their best chance after 30 minutes, shooting tamely at Cech after he had been played in by Rooney.