Manchester United kept up the pressure on Premiership leaders Arsenal after thrashing Derby County 4-1 at Old Trafford on Saturday. Ryan Giggs put the hosts in front when he scored his 100th goal for United in the 40th minute, notching on the rebound after Cristiano Ronaldo's initial shot was parried. Carlos Tevez doubled the advantage just before the break when he fired home from close range after a goal-mouth scramble. The Argentinean striker added the third on the hour mark after driving a shot into the bottom corner from inside the area. Substitute Steve Howard scored Derby's first away goal this season in the 76th minute. Portuguese winger Ronaldo completed the rout in stoppage time from the penalty spot. United are second in the league table with 36 points, just one adrift of leaders Arsenal, who take on Middlesbrough on Sunday. Elsewhere, Chelsea remained in the title race with an easy 2-0 victory over Sunderland. Andriy Shevchenko opened the scoring midway through the first half and Frank Lampard sealed the victory in the 75th minute.