Deco continued his fine start to life in the Premier League but Chelsea failed to match their first-day performance in a 1-0 win at Wigan.
The Portugal midfielder lashed home a free-kick in the third minute to hand the Blues three points against a resilient Latics side at the JJB Stadium.
Luiz Felipe Scolari’s men were a shadow of the side that romped to a 4-0 victory over Portsmouth in last weekend’s opener, but with two wins from two the Brazilian coach has already stolen a march on title rivals Arsenal and Manchester United.
Wigan were forced into a late change after goalkeeper Chris Kirkland injured his back in the pre-match warm-up.
Kirkland’s late withdrawal saw Mike Pollitt promoted to the starting XI, while Titus Bramble was also handed a recall in place of key defender Paul Scharner who was not in the squad.
An early mix-up between Deco and Michael Ballack gave the hosts a chance to break clear but Wilson Palacios lacked support and the danger soon passed.
It was the only chance Wigan got before former Barcelona star Deco fired Chelsea in front with an inch-perfect free-kick.
Lee Cattermole was penalised just outside the box and, with just three minutes on the clock, Deco curled the ball past a helpless Pollitt.
To their credit, the Latics hit back hard. First Palacios and then Amr Zaki forced Petr Cech into smart saves at his near post, while Antonio Valencia was stretched just too far as he attempted to strike a loose ball from 18 yards.
The match continued at breakneck speed – a classic Premier League match for the watching Fabio Capello – with Jose Bosingwa creating and conceding chances down Chelsea’s right flank.
Blues skipper John Terry was shown a yellow card in the 14th minute for impeding Emile Heskey and Wigan continued to threaten, with a speculative Cattermole effort briefly worrying Cech in the away goal.
Newly-crowned England skipper Terry went close himself after 17 minutes, heading over from six yards from a Frank Lampard corner.
Chelsea were looking uncomfortable at the back and needed a somewhat cynical foul by Bosingwa to prevent another Wigan counter in the 22nd minute.
Zaki was next to test Cech, forcing a good save after some fine build-up play from Cattermole and an unusually advanced Emmerson Boyce.
Mario Melchiot, Wigan’s skipper and a former Chelsea player, was also a threat, overlapping busily down the right and spraying an impressive array of passes.
The Dutchman was called into action in defence after 35 minutes, heading clear a dangerous-looking Nicolas Anelka cross to deny Ballack a tap-in.
Anelka was then denied a penalty after crashing to the turf with Boyce and Melchiot in attendance.
A Terry error gave Wigan one more chance to go level before the break but Heskey was unable to fashion a shooting chance from Zaki’s clever through-ball.
Wigan boss Steve Bruce used the break to restructure, replacing an off-colour Jason Koumas with winger Daniel de Ridder.
Chelsea started the second half as nervily as they finished the first – a breakdown in communication between Ricardo Carvalho and Cech almost gifting the hosts the softest of chances.
There was room for improvement in their forward play too, Anelka and Ashley Cole conspiring to lose possession on the edge of the area after an incisive Deco breakaway.
Joe Cole, putting in one of his less effective displays, was replaced before the hour mark with Salomon Kalou, now back from the Olympics, getting a first chance to impress Scolari.
Frank Lampard attempted to rouse Chelsea, scooping a high pass down the centre channel where Anelka, also struggling to make an impact, was jostled off the ball.
Michael Essien, having spent much of the afternoon anchoring the midfield, then had the half’s first attempt on goal, screwing a low shot to Pollitt’s right.
At last Chelsea started to create space and Wigan had Cattermole to thank for a superb saving tackle on the six-yard line in the 69th minute.
Carvalho was cautioned for a petulant kick at Zaki after 73 minutes but, in stark contrast to Deco, De Ridder’s set-piece delivery was dismal.
Indeed, it neatly summarised the difference between the sides.
The increasingly impressive Zaki then carved his way between Bosingwa and Essien, earning a corner with an exhilarating run.
He followed up 10 minutes from time with a tantalising left-wing cross which just evaded Heskey and resulted in a tame effort from De Ridder.
Substitute Olivier Kapo had Wigan’s best chance late on, making Cech dive full stretch to divert a skidding shot just wide of the post.