Paul Scholes marked his 600th Manchester United appearance in trademark fashion, supplying a great through ball that could eventually seal an 18th league championship for the Red Devils.
Chelsea's failure to beat Everton at Stamford Bridge leaves Liverpool as United's only realistic title rivals. Goals from Wayne Rooney and Michael Carrick mean Sir Alex Ferguson's men are now three points clear of their north-west rivals, with a match in hand.
It would be Scholes' ninth title medal. He deserves it for the sublime defence-splitting pass that set up Carrick seven minutes from time after United had failed to capitalise on Rooney's early opener.
Unusually for Scholes, until his telling late intervention he was fairly subdued as he joined Bill Foulkes, Sir Bobby Charlton and long-time team-mate Giggs in United's exclusive 600 club.
In fact, it was midfield partner Anderson and evergreen Giggs - who has now turned out an incredible 799 times for his only professional club - who caught the eye.
The pair were at the heart of most United attacking moves, combining in brilliant fashion for Rooney's early opener.
As Sir Alex Ferguson is well aware, quick goals are vital at this stage of the season, when nerves can create so many problems at both ends of the table.
So the United manager must have been delighted to see Anderson sent Giggs flying down the left flank with a brilliant reverse pass that found the Welshman just onside.
With 10 championship medals to his name, Giggs is not in the habit of panicking in such situations. And he calmly rolled his cross along the six-yard box, where Rooney gleefully tapped him.
Had Rooney been allowed to dart onto another precise Giggs pass at the end of a one-sided opening period, United would have had the victory they craved wrapped up with half the match remaining.
Instead, a very marginal offside decision went against them, as did a failure to convert a series of excellent chances, the best of which fell to Giggs.
Cristiano Ronaldo was the provider with a low cross from the right. Giggs' deft chip sailed over David James but bounced agonisingly wide of the post.
Substitute John O'Shea, who replaced Gary Neville shortly after Rooney's opener, had a header cleared off the line by Nadir Belhadj, with Giggs spurning another opportunity after Rooney had sent him through, United's stand-in skipper firing straight at James.
The half-time introduction of Jermaine Pennant brought some pace to Portsmouth's forward line. The problem for Pompey was they struggled to get into an area where it might be exploited.
On the one occasion they did, Glen Johnson was the provider. But Edwin van der Sar read his idea and pushed the England defender's low cross away from Peter Crouch.
Van der Sar was one of nine changes to Ferguson's FA Cup semi-final line-up.
Yet still the United manager could afford to leave Rio Ferdinand out altogether and have both Dimitar Berbatov and Carlos Tevez on the bench.
And once O'Shea had limped off, leaving Ferguson with a single remaining substitution, it was the Argentina star most United fans wanted to see introduced.
By then, anxiety appeared to have set in. In addition to Johnson's cross, Van der Sar had to keep out a volley from Crouch and a far more dangerous header from the same man that seemed destined for the bottom corner.
Rooney would have restored a sense of calm if he had finished instead of firing straight at James after shrugging off the attentions of Johnson to reach Van der Sar's long punt forward.
Yet Portsmouth's urgency left Ferguson to conclude neither Tevez nor Berbatov would be needed, bringing on Michael Carrick instead to help steady the ship.
The tactic worked a dream, although probably not in the way Ferguson imagined as the England man collected Scholes' superb pass and finished smartly.
It left Pompey dangling precariously six points above the drop zone, facing a crucial trip to Newcastle United on Monday.
By then, United will be getting ready to face Arsenal in a Champions League semi-final, with Scholes hoping another of those cherished title medals is within touching distance.
(From Website : http://www.premierleague.com/page/MatchReports/0,,12306~44741,00.html)
