Willian silenced PAOK Salonika as Chelsea enjoyed a winning start to their Europa League campaign in Thessaloniki.
Maurizio Sarri anticipated this would be the most difficult match of Group L, which also features Belarus' BATE Borisov and Vidi of Hungary, but Chelsea squandered numerous chances to make this an easy evening at Stadio Toumba.
Willian's seventh-minute strike was the difference in a 1-0 victory for the Blues, who have five wins from five Premier League games, with Pedro and Alvaro Morata spurning opportunities to add to the lead.
The Brazil midfielder on the eve of the match had insisted he always wanted to stay at Chelsea after speculation of a summer move to Manchester United or Barcelona.
He was named captain for the night and his early strike temporarily quietened the raucous home support after Ross Barkley's surge through the porous PAOK defence.
Chelsea chairman Bruce Buck had handed out packets of crisps to travelling fans, who had to gather four hours ahead of kick-off to take buses to the stadium.
The locals opted for firecrackers and flares, which could prompt disciplinary action from UEFA.
Chelsea won this tournament in May 2013, after suffering the ignominy of parachuting in from the Champions League while holders.
Eden Hazard, David Luiz - two survivors from five years ago - and Mateo Kovacic were left at home, with Sunday's Premier League clash at West Ham and Wednesday's Carabao Cup trip to Liverpool in mind.
Sarri made two further changes from the side which began last Saturday's 4-1 win over Cardiff.
Cesar Azpilicueta and Olivier Giroud dropped to the bench, alongside Ruben Loftus-Cheek and Gary Cahill, who again missed out on starts. For Cahill, last season's captain, it was a first involvement in the squad this season.
Willian, wearing the armband, stayed onside to receive Barkley's pass and struck a weak shot which squeezed under PAOK goalkeeper Alexandros Paschalakis.
It looked like the start of a rout which never materialised.
Morata controlled Antonio Rudiger's long pass and sent a shot wide across goal and next drilled over after making space for himself in the left side of the area.
A Willian corner almost had enough swerve to go in but instead was met at an acute angle by Morata. He could do little but turn it into the side-netting.
Marcos Alonso's defence-splitting pass then found Pedro, who fired straight at Paschalakis. Morata headed wide from the resulting corner.
Leo Jaba highlighted Alonso's need to improve defensively, but otherwise PAOK caused Chelsea few defensive concerns.
Willian missed the chance to double the lead early in the second half after build-up play involving Morata, Pedro and Barkley.
Willian then volleyed wildly over when in space in the area after a Barkley header had bounced back off Morata.
An Alonso shot deflected wide before he departed, with Azpilicueta coming on and assuming the captain's armband.
Cesc Fabregas also came on, for Jorginho, and later Morata departed for Giroud. The Spain striker appeared frustrated not to have seized his chance.
Pedro struck a fierce shot which Paschalakis was equal to, with Chelsea anxious now to add to their slim advantage.
PAOK substitute Diego Biseswar shot at Kepa Arrizabalaga before Amr Warda was booked for grabbing Rudiger as PAOK finally got to grips with Chelsea in stoppage time.
Pedro went off looking groggy after being caught by Paschalakis' knee, although it appeared his left shoulder was the greater concern and he may be ruled out of Sunday's trip to the London Stadium.