Maurizio Sarri rued the profligacy of Chelsea and striker Alvaro Morata after Thursday night’s 1-0 win at PAOK Salonika.
Willian’s seventh-minute strike was the difference for the Blues, who have five wins from five Premier League games, but Pedro and Morata spurned numerous opportunities to add to the lead.
“We were in control of the match for 90 minutes,” head coach Sarri said. “We have had a lot of opportunities. We missed several.
“So I am really very happy with the three points, very happy with the performance, but I am not very happy with the result.
“When it is time to kill the match we have to kill the match.”
Morata began his Chelsea career with seven goals in eight games last season, but has appeared shorn of confidence of late. He has scored once this season, in August’s win over Arsenal.
Sarri is scratching his head at how to revive Morata’s morale, but praised his improved movement.
“Alvaro has to gain confidence with one, two, three goals,” Sarri added. “I am not able to give him confidence. In this match he has had three, four opportunities. He was unlucky.
“I hope for him that in the future I can try to help him, but the confidence can come only with goals.
“I have to say also, for maybe the first time in this season Alvaro was ready in the box. He was on the ball and was active.”
The one major blot was a stoppage-time shoulder injury for Pedro, potentially ruling him out of Sunday’s trip to West Ham, which comes ahead of Wednesday’s Carabao Cup clash at Liverpool and the Reds’ visit to Stamford Bridge on September 29.
Sarri said: “I don’t know exactly the situation. I have spoken with the doctor, but only for a few seconds. The doctor told me that probably it’s not a very serious injury.”
It was PAOK’s first loss to English opposition after four prior games.
PAOK boss Razvan Lucescu said: “Maybe we started with too much respect. We also made a mistake for the first goal.
“I’m satisfied with the huge efforts from the players, who ran a lot and kept their heads. As for the result, you’re never satisfied when you lose, but we faced one of Europe’s best teams at the moment.
“We were able to balance the game and situation in the second half. At that moment we started to push more and Chelsea – probably after their huge effort in the first half when they moved the ball a lot, ran a lot, and created good opportunities – lost their freshness.
“We then could have created possibilities to draw the game.”