Jose Mourinho's Porto homecoming didn't go to plan as the Blues were beaten 2-1 by his former club.
Chelsea lost to Porto on Mourinho's first return in 2004-05 and history repeated itself at Estadio do Dragao as Andre Andre and Maicon scored either side of Willian's free-kick in the Group G clash.
Eden Hazard dropped to the substitutes bench alongside captain John Terry and Nemanja Matic as Mourinho proved there were no untouchables in his squad.
Porto 2-1 Chelsea in pictures:
His hardline approach also followed his outspoken criticism of his players' attitude, but Mourinho's words did not have the desired effect as Chelsea looked vulnerable throughout.
Yacine Brahimi waltzed inside Branislav Ivanovic and behind Pedro, then fired in a shot which Asmir Begovic punched only as far as Andre, who hooked the ball in.
Willian replied with a delightful curling free-kick on the stroke of half-time, but then woeful defending allowed Maicon to head in a corner seven minutes into the second half.
