Portsmouth stunned Manchester United with a smash and grab 1-0 victory at Old Trafford on Saturday to reach the FA Cup semi-finals.Pompey were under siege for long periods but a penalty 12 minutes from time by Sulley Muntari after United keeper Tomasz Kuszczak was sent off for fouling Milan Baros gave them a first victory at Old Trafford since 1957. The bigger suprise though, was later at night when Championship side Barnsley dumped Chelsea out with a 1-0 victory. Kayode Odejayi scored in the second half.Portsmouth can now look forward to a Wembley semi-final, the first time they have reached the last four of the FA Cup since losing to Liverpool in 1992. “It was the worst draw we could have got but it was a great performance and a great result,” Portsmouth manager Harry Redknapp, who memorably led Bournemouth to a 1984 Cup victory over United said. Portsmouth managed comfortably enough in the first half with Glen Johnson’s headed clearance from Carlos Tevez and a loud United penalty appeal when Sylvain Distin barged Cristiano Ronaldo off the ball their most worrying moments. After the break, however, they were forced into desperate defence against the Premier League champions with Sol Campbell outstanding at the heart of the Pompey resistance.Fergie hints at 2012 exitManchester: Manchester United manager Alex Ferguson’s plan is retire on top and leave a thriving club to his successor. “That’s the perfect time as you know you’ve done your job,” he said Friday. “When I make the decision I would be satisfied the club is in good hands.” In a French radio interview which emerged Friday, Ferguson said he was contemplating stepping down within the next three years, but the veteran coach later downplayed that time frame with reporters.