A second-half header from Nicolas Anelka ensured Chelsea defeated Porto 1-0 to secure top spot in UEFA Champions League Group D.

Portuguese Liga champions Porto enjoyed the better of the first half at Estadio do Dragao, with Fernando Belluschi seeing a rasping effort hit the crossbar.

But the Blues were improved after the interval and Anelka grabbed his sixth goal of the season in the 69th minute as he headed home from a Florent Malouda cross.

The result ensures Chelsea finish at the summit of Group D with December's game against Apoel Nicosia at Stamford Bridge still to play.

Bright

Chelsea were quickly into their stride against Porto in a surprisingly sparsely populated stadium.

There were many empty seats among the Porto sections of the ground and the atmosphere which accompanied the start of the game was hardly intimidating for Chelsea.

In the sixth minute, Malouda, scorer of their wonderful opener against Wolves last Saturday, was off target with a 25-yard low drive which drifted wide of the target.

In the 15th minute, Chelsea won a corner when Didier Drogba's shot was turned over by Beto. Unfortunately for the English side, Deco floated the flag-kick over everybody in the penalty area.

The Portugal international was given a warm reception by the Porto fans in that part of the ground.

In the 18th minute Michael Ballack almost finished off a neat move by the Blues but his final shot was deflected for another wasted corner.

But the home side almost took the lead in the 20th minute with their first real attack of the game.

Belluschi's 25-yard drive was palmed into the path of Radamel Falcao Garcia by Petr Cech but the Chelsea goalkeeper redeemed himself with another fine save at the feet of the Porto forward.

Porto were unlucky not to break the deadlock in the 29th minute when Argentine Belluschi, playing his first game for a month, again tried his luck from 20 yards.

This time his shot beat Cech in the Chelsea goal but rebounded off the crossbar to safety.

Chelsea were living dangerously but Porto did not appear to have to guile to create anything other than the occasional long-range effort.

A 20-yard drive from Deco flashed past Beto's left-hand upright in the 36th minute.

Thrilling

It was hardly a thrilling spectacle and the stay-away Porto fans clearly made the right decision.

Jesualdo Ferreira's side may have come close to scoring with two long-range shots but Chelsea had coped easily with much of their attacking play.

Time and again Chelsea wasted the ball in good areas, with full-back Branislav Ivanovic one of the main culprits.

Chelsea had created nothing in an opening half that was instantly forgettable.

The English outfit had made a much better start to the second half and Deco sent a shot flashing beyond the far post in the 52nd minute.

Moments later, Malouda drilled two low crosses into the penalty area but they eluded the Chelsea strikers on each occasion.

At least there was more purpose about Chelsea's play now and Ballack was booked for a challenge on Cristian Rodriguez as the Porto player threatened to run clear.

Porto brought on Hulk to great cheers from the home fans in the 59th minute. The Brazilian striker replaced Silvestre Varela.

In the 67th minute Chelsea replaced the ineffective Ballack with Michael Essien.

Essien, who scored two goals against Wolves last weekend, was left out of the starting line-up after collecting a minor knock on his knee.

But clearly coach Carlo Ancelotti was anxious to add some drive to a rather lack-lustre midfield.

It brought instant results, although not from Essien. Yuri Zhirkov broke down the left and his pass found Malouda inside the penalty area.

This time the winger's cross found the head of Anelka as the France international stooped to head his third goal of the Euro campaign in the 69th minute.

It was Anelka's sixth goal of the season and his first in eight games for the Blues.

FC Porto	Team Statistics	Chelsea
0	Goals	1
0	1st Half Goals	0
6	Shots on Target	2
5	Shots off Target	8
7	Blocked Shots	3
2	Corners	5
15	Fouls	13
5	Offsides	2
2	Yellow Cards	1
0	Red Cards	0
80.7	Passing Success	84.2
37	Tackles	26
75.7	Tackles Success	73.1
43.8	Possession	56.2
49.5	Territorial Advantage	50.5

Teams

Porto  Beto, Sapenaru (Farias 80), Rolando, Alves, Pereira, Belluschi (Guarin 72), Fernando, Meireles, Varela (Hulk 60), Falcao, Rodriguez
Subs Not Used Nuno, Valeri, Macion, Helton
Booked  Fernando, Meireles
Goals 

Chelsea  Cech, Ivanovic, Carvalho, Terry, Zhirkov, Mikel, Ballack (Essien 68), Malouda, Deco (J. Cole 76), Anelka, Drogba
Subs Not Used  Turnbull, A. Cole, Alex, Belletti, Kalou
Booked  Ballack
Goals  Anelka 69

Attendance 35,000

Referee J. Eriksson (Sweden)