Luiz Felipe Scolari's reign as Chelsea boss started in style with an impressive win against Portsmouth.
Joe Cole slid home Michael Ballack's pass after 12 minutes and Nicolas Anelka headed in Deco's cross from close range in the 26th minute.
Frank Lampard added the third from the spot on the stroke of half-time after Sylvain Distin handled.
And Deco crowned a superb Chelsea debut with a swerving shot from 25 yards a minute from the end.
Scolari hopes to bring a more attractive brand of football to Stamford Bridge - and his new charges certainly delivered in their first Premier League game.
But the display should also be placed in the context of a truly wretched performance from Harry Redknapp's side, who looked a shadow of the unit that had an impressive campaign last season.
Chelsea took only 12 minutes to score the first goal of the Scolari era, and it was perfectly fashioned as Ballack's pass with the outside of his foot found Joe Cole, who slid a finish beyond James.
Anelka almost added a second when he was denied by James after racing clear - but it was only a temporary reprieve for Portsmouth as the striker was on target after 26 minutes.
Jose Bosingwa's cross was retrieved by Deco, who was having an outstanding first half, and Anelka headed home with James stranded out of position.
Anelka's pace was proving too much for Portsmouth, and he shot narrowly wide after racing clear.
Chelsea lost Ballack to injury after 37 minutes, but his replacement Florent Malouda almost had an instant impact with a driven cross that flashed across the face of goal.
Portsmouth had a half-chance when Petr Cech was forced into a block from Niko Kranjcar, the Chelsea keeper recovering to block another effort from Peter Crouch.
Portsmouth were being totally outclassed, and the scoreline was given a more realistic appearance when Chelsea took a three-goal lead in the dying seconds of the opening period.
606: DEBATE
Chelsea continued to press after the break, with both Anelka and Joe Cole only inches away from adding to Portsmouth's misery.
Little had been seen of Portsmouth's new strike force of Crouch and Jermain Defoe, but it finally showed glimpses of promise with 13 minutes left.
Crouch headed a long ball into Defoe's path, but he was stretching and steered his finish wide.
Chelsea deserved a fourth goal, and it was fitting that Deco got it with two minutes to go, firing in from 25 yards via the hands of James, who should have done better.
Owner Roman Abramovich was all smiles at the final whistle as he revelled in the first impressions created by his new manager.
Chelsea boss Luiz Felipe Scolari:
"I think the owner is happy, like the other fans.
"Portsmouth didn't think we would play like we did and we were more aggressive than last season. I think they were surprised by our team.
"I only give the players the freedom to play and allow them to express their style."
Portsmouth boss Harry Redknapp:
"You're not going to break into the top four. No-one is this year.
"Spurs have got a squad and can't even win at Middlesbrough, so you start forgetting about them.
"The top four are on another level. We've improved our standard in the last three or four years but, today, you step up into a different level."
Chelsea: Cech, Bosingwa (Ferreira 83), Carvalho, Terry, Ashley Cole, Ballack (Malouda 38), Lampard, Obi, Deco, Joe Cole (Wright-Phillips 78), Anelka.
Subs Not Used: Hilario, Di Santo, Bridge, Alex.
Goals: Joe Cole 12, Anelka 26, Lampard 45 pen, Deco 89.
Portsmouth: James, Kaboul, Campbell, Distin, Hreidarsson, Johnson, Diarra (Mvuemba 68), Diop, Kranjcar (Thomas 73), Defoe, Crouch.
Subs Not Used: Ashdown, Lauren, Utaka, Cranie, Traore.
Booked: James.
Att: 41,468
Ref: Mike Dean (Wirral).
BBC Sport Player Rater man of the match: Chelsea's Deco 7.62 (on 90 minutes).
• Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.
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