London - Maurizio Sarri's fear of a slow start at Chelsea may have been unfounded but the head coach insists his side are still very much a work in progress.
Chelsea will travel to Newcastle on Sunday aiming to make it three wins from as many Premier League games this season.
Having voiced concerns about how quickly his new players would adapt to his methods, Sarri's problems right now appear to revolve around who to leave out of his line-up.
Nevertheless, he saw enough in the Community Shield defeat by Manchester City and last weekend's narrow home victory against Arsenal to confirm him in the view that, defensively, there is still work to be done.
Against the Gunners, it took a late winner from left-back Marcos Alonso to secure a 3-2 victory after Henrikh Mkhitaryan and Alex Iwobi had cancelled out Chelsea's early two-goal lead.
And while Newcastle might not have the firepower to threaten the Blues in the way City and Arsenal did, Sarri knows his hopes of steering the club back into the top four will not be helped by a leaky back-line.
The 59-year-old said Chelsea's defence was not still up to speed when he explained the ongoing absence of Gary Cahill, insisting it was harder for defenders to adjust to his methods than more attack-minded players.
Like Chelsea playmaker Eden Hazard, Cahill returned to pre-season training later than some of his colleagues having been a member of the England squad that reached the World Cup semi-finals in Russia.
And with Sarri determined to impose a back-four after two seasons of Antonio Conte's preferred 3-4-3 formation, there are fewer openings for a centre-back.
"I think that, in this moment, for a defender it's more difficult to play in my team after only 20 days of training," said Sarri.
"I am not worried about the defensive phase because, when I arrive at a new team, usually I have problems with the defensive phase for two or three months. So I think it's normal for me."
Sarri insisted a back-four was crucial to his plans to introduce the approach dubbed 'Sarri-ball' at former club Napoli to England.
"I am not able to play with five defenders, because we are trying to defend by looking only at the ball," he said.
"In this way, if I defend with five defenders, I lose immediately metres on the pitch. I am not able. I tried five years ago, but it's not my way."
The speed with which the players adapt to the changing requirements at the back could determine how successful Sarri is in his first season in England.
He can be satisfied, though, that with Hazard due to return to full fitness soon, his side's attacking strengths should provide the breathing space needed to adjust.
Meanwhile Newcastle will be without defender Isaac Hayden as he starts a three-match ban after being sent off in a goalless draw away to Cardiff last Saturday.
Kenedy, who missed a penalty in that match, will also be absent as the 22-year-old Brazilian loan signing from Chelsea is ineligible to play against his parent club.
Many Newcastle fans remain frustrated by owner Mike Ashley's refusal to let Rafael Benitez spend heavily in the transfer window.
But Magpies manager Benitez urged supporters to back the team rather than protest against Ashley once they were inside St James' Park.
"What I would say is just be sure that when you go to the stadium, you support the team because it's the only way for us to be stronger," Benitez said.