Chelsea sealed top spot in Champions League Group D on Wednesday night with a hard-fought 1-0 win over Porto in Portugal.

With both sides already through to the last 16 there was only top spot up for grabs and Chelsea duly obliged with one game to spare as Nicolas Anelka's second-half header handed Carlo Ancelotti's men the points.

After a tentative start Michael Ballack almost finished off a neat move by the Blues but his final shot was deflected for a corner.

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

Fernando Belluschi's 25-yard drive was palmed into the path of Falcao 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 Argentinian 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.

For Chelsea a 20-yard drive from Deco flashed past Beto's left-hand upright as the first half drew to a close.

At the start of the second period Deco flashed a shot just wide of the left upright, but Chelsea didn't have to wait too long before breaking the deadlock.

With 69 minutes on the clock Yuri Zhirkov broke down the left and played in Florent Malouda, whose cross was headed home from close range by Anelka.

Substitute Hulk almost headed Porto level minutes later but Zhirkov managed to get his body between himself and the Porto man to deny the opportunity.

Hulk was again in the thick of the action with nine minutes remaining but after bursting through the Chelsea rearguard he shot straight at Cech.