The Premier League new boys took a surprise lead early in the game before Coty responded with three goals inside four minutes.
The boss was keen to praise Kieran McKenna’s side as well as his own players’ performance.
“The team started really well on the front foot,” said Pep.
“We played really good, but the opponents made an exceptional action and credit to them.
“We started on the front foot, always we talk about that, and it is not good enough for what we achieve.
“This is the only problem we can have. When I see how we started and how much respect we have for them.
“I said as they come from the Championship to the Premier League, it’s because they have something special.
“I saw the game against Liverpool and how tough it was. At home in their own stadium, it was maybe more difficult than it was today.
“But we played on the front foot and in the first half we created enough for 4 or 5 goals and the game would be over.
“At 3-1 it is always uh-oh, score a second goal and it would have been a problem.
“We behaved at a level that we started at Stamford Bridge today. With the lack of preparation we had, to go two for two is really good.”
Watch Pep’s full press conference on the video above.