Chelsea claimed their third win in a row to tighten the pressure in the Premiership title race after Scott Parker grabbed an early goal to open his Blues account and substitute Hernan Crespo clinched it late on in his first spell of action after six games out through a calf injury.

There were celebrations in two quarters of London after Manchester United suffered a shock home defeat by Middlesbrough and let Chelsea close to within a point of them, although they are still six behind Arsenal.

Parker, who had to sit out a possible home debut against former club Charlton last Sunday under the terms of his transfer, blazed a spectacular opener after a smart exchange with Adrian Mutu which followed one of many penetrating raids by Jesper Gronkjaer.

Armed with that 15th minute lead, Chelsea gave every impression they would drive home their dominance.

But it was not until deep into the second period when Jimmy Floyd Hasselbaink emerged from the bench in search of his 100th Premiership goal that they quelled Pompey's fire completely.

Hasselbaink, match-winner with a penalty last Sunday, lobbed a Frank Lampard pass against the bar with 12 minutes left and saw Argentinian Crespo, booked just three minutes earlier for diving and trying to win a penalty, chest the rebounding ball into an empty net for his ninth goal in 13 games for Chelsea.

For a long spell in the first half, Chelsea had Harry Redknapp's Premiership newcomers under the cosh.

Minus the injured Teddy Sheringham, Pompey were chasing shadows for a spell as Lampard, Parker and much-abused former Southampton star Wayne Bridge popped the ball around, finding space and feeding Gronkjaer at every opportunity.

And yet a blunder by stand-in goalkeeper Neil Sullivan should have gifted Portsmouth a 25th-minute equaliser - only for Aiyegbeni Yakubu to miss a sitter.

Sullivan, keeping the jersey warm while Carlo Cudicini tries to recover from a groin injury ahead of two massive clashes with Arsenal over the next two weekends, failed to make a routine clearance, striking the ball against team-mate John Terry.

It fell perfectly into the stride of Yakubu but the young Nigerian lost his cool and blasted high over the bar with the goal at his mercy.

Chelsea, with several of their star-studded squad back in action having had to do without a dozen injured or unavailable against Charlton, were at their most dangerous when breaking from deep positions.

But, encouraged by the chance for Yakubu, stop-gap skipper Nigel Quashie had a go from the edge of the area, skewering a low effort across the face of goal.

And it was sheer tough luck on Patrik Berger when just after the half-hour, the former Liverpool star let fly with his left foot from 30 yards, beat Sullivan's dive but saw his shot bounce away off the foot of a post.

Sullivan redeemed himself for his earlier error when Yakubu's angled drive demanded a sharp save.

But the former Tottenham keeper was barely troubled in the second half, thanks to the cool and gritty defending of John Terry and William Gallas and despite the pot-shots of newcomer Lomana LuaLua.

Portsmouth have now won only two of their last 12 games in the League and survival will remain a struggle but Chelsea are well set up now for their double date with the Gunners.

Teams

Portsmouth Hislop, Primus, De Zeeuw, Pasanen, Stefanovic, Quashie, Faye, Berger (LuaLua 56), Berkovic (Taylor 84), Mornar, Yakubu.

Subs Not Used: Wapenaar, Curtis, Hughes.

Booked: Stefanovic.

Chelsea Sullivan, Melchiot, Gallas, Terry, Bridge, Gronkjaer, Parker (Cole 74), Lampard, Makelele, Mutu (Crespo 62), Gudjohnsen (Hasselbaink 71).

Subs Not Used: Ambrosio, Huth.

Booked: Parker, Crespo.

Goals: Parker 17, Crespo 79.

Att: 20,140

Ref: G Poll (Hertfordshire).