AVRAM Grant's reign at Chelsea ended with defeat on penalties to Manchester United and his first game in charge of Portsmouth saw Red Devils forward Wayne Rooney score two crucial spot-kicks within his hat-trick at Fratton Park.

Grant, who has taken over from Paul Hart and will be rubber-stamped as manager next week when paperwork is completed, could not have asked for a tougher opening game than against the Premier League champions but there was hope of a result when Kevin-Prince Boateng levelled, also with a penalty.

Sir Alex Ferguson served the first half of his two-match touchline ban for criticising referee Alan Wiley and he may ask why Mike Dean awarded Pompey their penalty - but he will have no complaints with the way Rooney wrapped up the points after the break. Ryan Giggs added the fourth late on.

Grant and Ferguson last faced each other 18 months ago during the Champions League final in Moscow when John Terry lost his footing in the penalty shoot-out and Chelsea let the European crown slip away.

There was a downpour on this occasion too. This time Grant was in charge of a team that started the weekend bottom of the league and three points from their nearest rivals, while Ferguson was looking to gain ground on leaders Chelsea.

If Pompey have a fighting chance of staying up Grant will need the players left over from a fire sale over the last year - but he was denied the service of England goalkeeper David James due to a calf injury and Asmir Begovic started.

For United, it was a case of whether Ferguson's absence in the dressing room would be a factor, although he had communication lines in place to assistant Mike Phelan and was hoping the din at Pompey's "rickety" stadium would not drown him out.

Sat next to chief executive David Gill in the directors' box, Ferguson saw his side enjoy plenty of possession early on and press when the hosts were on the ball.

Paul Scholes had the first effort of the match, firing over when Giggs rolled a corner to the edge of the penalty area where his team-mate was left unmarked.

Pompey threatened within a minute and Tomasz Kuszczak, in because Edwin van der Sar had a knock to his knee, was required to block bravely when a ball was lobbed over the top of United's defence and found Aruna Dindane.

Encouraged by this opening, Dindane also fired wide from long distance and headed off-target when unmarked from Jamie O'Hara's cross. O'Hara himself had an effort tipped over after Frederic Piquionne nodded in his direction on the edge of the area.

Despite the Pompey attacks, United were ahead in the 25th minute through Rooney.

Antonio Valencia burst forward and exchanged passes with Rooney, and when the winger pulled the ball back for his team-mate in the penalty area, the England forward waited for a clumsy challenge to arrive from Michael Brown.

Dean pointed to the spot immediately and Rooney tucked away the penalty.

Pompey were level, however, on the half-hour mark, although why Dean awarded it was open to debate. Kuszczak climbed above Piquionne, who appeared to have his shirt pulled by Nemanja Vidic.

With United in shock, Boateng smashed in the penalty after missing against Stoke last time out.

Pompey enjoyed a spell of pressure before the break but United were ahead three minutes after the restart.

There was nothing controversial about this effort, just Giggs weighting the ball perfectly through Pompey's defence for Rooney to place his finish home, his 10th of the season for United.

His hat-trick came in the 54th minute, from the penalty spot. Piquionne was penalised for fouling Giggs - and Rooney sent Begovic the wrong way from 12 yards.

Valencia could have added to the goals when he waltzed through the Pompey defence.

Boateng had Pompey's best chance to get back in the game but he fired over from a promising position, and there would be no way back for Grant's men.

Giggs netted with a free-kick three minutes from full-time for their fourth goal, while John Utaka hit the crossbar with a scissors-kick at the death for Pompey.