Chelsea manager Maurizio Sarri said the Europa League could "be a problem" later in the season after his side began their campaign with a 1-0 win at PAOK Salonika.
Willian's early goal from Ross Barkley's lay-off was enough for a much-changed Blues side to maintain their winning start to the season in Greece, despite playing in front of a raucous sold-out crowd in Thessaloniki.
"For an English team the Europa League is a very difficult competition," said Sarri. "In Italy, if I play in Greece on Thursday I can ask to play on Monday night, but I have to play again in 63 hours. I don't know in the future.
"It is not a big problem now because we have played only six matches but in the future, it may be a problem. I hope to qualify before the last one or two matches of the group stage."
Sarri made five changes from Saturday's 4-1 win against Cardiff with Eden Hazard, who Sarri says has complained of tiredness twice in the last month, being rested along with David Luiz and Mateo Kovacic. But while most of the Chelsea players were composed throughout, Alvaro Morata endured a frustrating night after replacing Olivier Giroud up front.
"Morata had three or four opportunities, he was unlucky," said Sarri. "I hope in the future I can try to help him, but the confidence comes only with goals. I am not able to give him confidence.
"But I have to say also that for the first time this season he was very ready in the box. He was on the ball, he was active."
GOALS:
7' Willian
TEAM STATS
STANDINGS GROUP L
PLAYER RATINGS -WHO SCORED
FACTS
Each of Chelsea's last 10 managers have won their first European game in charge, with Claudio Ranieri the last to fail to do so in September 2000 (0-2 v FC St Gallen).
Chelsea have won each of their last four games in the Europa League, a run which includes their final three games in 2012-13 when they won the competition.
Chelsea manager Maurizio Sarri has won all of his group stage games in the Europa League (seven out of seven), keeping five clean sheets in this run.
Ross Barkley's assist for Chelsea's goal was his first in club football since April 2017 for Everton against Leicester.
PAOK have failed to score in six of their last seven home games in the Europa League.
